Force, Mass, and Motion Alıştırma Soruları — Armed Services Vocational Aptitude Battery (ASVAB) — Sayfa 3

Soru 41Soru →

A heavy rectangular crate is being dragged across a level warehouse floor. If the crate is stopped, flipped to rest on its narrowest side, and then dragged again, how will the force of sliding friction change?

It remains the same.

It decreases because there is less surface area touching the floor.

It increases because the crate's weight is concentrated into a smaller area.

It changes because the crate's inertia is altered by its new position.

Cevabı ve açıklamayı göster

Cevap: It remains the same.

Cevap

The force of sliding friction remains the same.

The correct answer states that friction remains the same. According to the laws of classical physics, sliding (kinetic) friction is determined by multiplying the normal force (the weight of the crate) by the coefficient of friction (the material properties of the floor and crate). Because flipping the crate changes neither its overall weight nor the materials involved, the total frictional resistance remains unchanged.

Adım Adım Çözüm

1

Identify the factors that determine sliding friction.

Sliding friction relies on the normal force (the crate's weight) and the coefficient of friction (the roughness of the floor and crate materials).

These are the only physical variables present in the standard friction formula (

F = \mu N

).

2

Evaluate what changes when the crate is flipped.

The surface area touching the floor decreases, but the crate's mass, weight, and material remain exactly the same.

Flipping an object only changes its orientation, not its inherent properties.

3

Determine the impact of contact area on friction.

The frictional force does not change.

Because neither the normal force nor the surface materials have changed, the total resistance remains constant regardless of the contact area size.

Anahtar Kavram

Sliding friction depends only on the normal force and the coefficient of friction between the two surfaces, and is independent of the apparent area of contact.

Soru 42Soru →

During a training exercise, a signaling flare is launched vertically upward from ground level with an initial velocity of $30\text{ m/s}$ . Assuming air resistance is negligible and using the approximation $g = 10\text{ m/s}^2$ , how many seconds will it take for the flare to reach its maximum height?

Cevabı ve açıklamayı göster

Cevap: 3

Cevap

It will take 3 seconds for the flare to reach its maximum height.

At its maximum height, any vertically launched object momentarily stops before falling back down, meaning its instantaneous velocity is

0\text{ m/s}

. Given an initial upward velocity of

30\text{ m/s}

, gravity decreases this velocity by

10\text{ m/s}

for every passing second. Therefore, it takes exactly 3 seconds for gravity to completely counteract the initial upward speed (

30 / 10 = 3

).

Adım Adım Çözüm

1

Identify known variables and the final goal

v_i = 30\text{ m/s}

,

v_f = 0\text{ m/s}

(velocity is zero at the apex), and

a = -10\text{ m/s}^2

. The goal is to find time (

t

).

Establishing the initial and final states is required to choose the correct kinematic equation for free fall.

2

Select the appropriate kinematic formula

Use the equation

v_f = v_i + at

.

This formula connects initial velocity, final velocity, acceleration, and time, without needing to know the distance traveled.

3

Substitute the values and solve for

t

0 = 30 - 10t \Rightarrow 10t = 30 \Rightarrow t = 3

.

Solving the linear algebraic equation yields the exact time it takes for gravity to decelerate the flare to a stop.

Anahtar Kavram

Calculating the time to reach the apex of vertical projectile motion under uniform gravitational acceleration.

Soru 43Soru →

A twin-engine military cargo aircraft with a total mass of $80,000 \text{ kg}$ is accelerating down a runway for takeoff. Each of the two engines generates $140,000 \text{ N}$ of forward thrust. If the combined forces of rolling friction and aerodynamic drag opposing the aircraft's motion amount to $80,000 \text{ N}$ , what is the forward acceleration of the aircraft in $\text{m/s}^2$ ?

Cevabı ve açıklamayı göster

Cevap: 2.5

Cevap

The forward acceleration of the aircraft is 2.5 m/s².

To accurately determine the acceleration, one must first find the net force acting on the aircraft. The total forward thrust is the sum of both engines (

140,000 \text{ N} \times 2 = 280,000 \text{ N}

). Subtracting the opposing forces of friction and drag (

80,000 \text{ N}

) yields a net forward force of

200,000 \text{ N}

. Dividing this net force by the aircraft's mass of

80,000 \text{ kg}

gives a forward acceleration of

2.5 \text{ m/s}^2

.

Adım Adım Çözüm

1

Calculate the total forward thrust applied to the aircraft.

2 \times 140,000 \text{ N} = 280,000 \text{ N}

The aircraft has two engines, and the problem provides the thrust generated by each individual engine.

2

Calculate the net force (

F_{net}

) acting on the aircraft.

F_{net} = 280,000 \text{ N} - 80,000 \text{ N} = 200,000 \text{ N}

Net force is the vector sum of all forces. The opposing forces (drag and friction) must be subtracted from the forward thrust.

3

Apply Newton's Second Law to calculate the acceleration.

a = \frac{200,000 \text{ N}}{80,000 \text{ kg}} = 2.5 \text{ m/s}^2

According to Newton's Second Law, acceleration equals the net force divided by the mass (

a = \frac{F_{net}}{m}

).

Anahtar Kavram

Newton's Second Law of Motion (

F_{net} = ma

)

Soru 44Soru →

Match each mechanical design feature with its primary physical effect on friction or resistance.

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Cevabı ve açıklamayı göster

Cevap

Lubricating oil decreases sliding friction, ball bearings convert sliding friction to rolling friction, heavy tire treads increase static friction, and a streamlined aerodynamic shape reduces fluid resistance.

Each feature is a standard engineering method for managing a specific form of resistance based on its application. Lubricants handle sliding friction, bearings manage rotational contact by rolling, treads ensure static friction for grip, and aerodynamics handle fluid resistance in the air.

Adım Adım Çözüm

1

Analyze each mechanical design feature to determine what materials or surfaces are interacting.

Gears involve metal-on-metal sliding; axles involve rotational contact; tires interact directly with the ground; airplanes interact with the air.

Identifying the interacting materials reveals the specific type of physical resistance involved in each scenario.

2

Determine whether the design goal of the feature is to increase or decrease the physical resistance.

Tires need increased friction for grip, while gears, axles, and airplanes need decreased resistance for mechanical efficiency.

Matching the design goal (grip vs. efficiency) with the physical mechanism leads to the correct pairings.

Anahtar Kavram

Methods of Controlling Friction and Resistance

Soru 45Soru →

A logistics team is evaluating the force required to slide various solid steel crates across a dry, level concrete warehouse floor at a constant velocity. Assume the coefficient of kinetic friction remains constant for all steel-on-concrete contact.

Rank the following sliding scenarios from the GREATEST kinetic frictional resistance to the LEAST kinetic frictional resistance.

Öğeleri doğru sıraya koymak için sürükleyin

Cevabı ve açıklamayı göster

Cevap

The correct sequence from greatest to least frictional resistance is the 200-pound crate, followed by the 150-pound crate, the 100-pound crate, and finally the 50-pound crate.

According to the laws of sliding friction, kinetic frictional force depends entirely on the coefficient of friction and the normal force (the object's weight on a level surface). It is completely independent of the surface area in contact. Therefore, the friction is determined solely by the weight of the crates. Arranging them strictly from heaviest to lightest correctly orders them from greatest to least frictional resistance.

Adım Adım Çözüm

1

Identify the governing mathematical relationship for kinetic friction.

The formula for kinetic friction is

F_k = \mu_k \times F_N

, where

\mu_k

is the coefficient of kinetic friction and

F_N

is the normal force.

This establishes which physical properties actually affect sliding resistance.

2

Determine the impact of surface area on the calculation.

The apparent contact area (2 sq ft vs 10 sq ft) is not a variable in the friction equation.

According to Amontons' Second Law of Friction, dry sliding friction is independent of the apparent area of contact.

3

Calculate the normal force for each scenario.

On a level floor, the normal force is exactly equal to the weight of the object. The normal forces are 200 lbs, 150 lbs, 100 lbs, and 50 lbs.

The weight dictates how hard the two surfaces are pressed together.

4

Order the scenarios based on the normal force.

Highest to lowest normal force: 200 lbs, 150 lbs, 100 lbs, 50 lbs.

Because kinetic friction is directly proportional to normal force, ordering by weight correctly orders by total frictional resistance.

Anahtar Kavram

Amontons' Laws of Friction (Surface Area Independence)

Soru 46Soru →

A mechanic attempts to push a heavy, stationary tool cabinet mounted on well-lubricated casters across a level garage floor. Despite the low friction, it requires a significant initial effort from the mechanic just to get the cabinet moving. Which concept best explains why the cabinet resists this initial change in its state of rest?

The cabinet's inertia, which naturally opposes any change to its state of motion.

An equal and opposite reaction force generated by the cabinet actively pushing back.

The cabinet's total weight, which must be completely overcome to move it horizontally.

The large surface area of the casters, which creates a high static frictional force.

Cevabı ve açıklamayı göster

Cevap: The cabinet's inertia, which naturally opposes any change to its state of motion.

Cevap

The concept that best explains the resistance is the cabinet's inertia, which naturally opposes any change to its state of motion.

The correct answer accurately identifies inertia as the property of matter that resists any change in its state of motion. Because the cabinet has a large mass, its inertia is high, requiring a significant unbalanced force to accelerate it from rest, regardless of how low the friction is.

Adım Adım Çözüm

1

Analyze the conditions given in the scenario.

The cabinet is heavy (large mass) and rests on well-lubricated casters (low friction).

Identifying the forces at play helps rule out friction as the primary cause of resistance.

2

Identify the relevant mechanical principle.

The resistance to a change in motion (from rest to moving) is called inertia, governed by Newton's First Law.

Matching the physical behavior to the correct physical law determines the correct answer.

Anahtar Kavram

Newton's First Law of Motion (Inertia)

Soru 47Soru →

A technician is modifying a heavy steel sliding door that currently drags directly along a flat metal base. To significantly reduce the frictional resistance required to open and close the door, which of the following design changes would be the most effective?

Incorporating steel ball bearings or roller wheels between the door and the base.

Widening the base track so the door's weight is distributed over a larger surface area.

Increasing the total mass of the door so it carries more momentum once pushed.

Decreasing the pushing speed to minimize the reaction force from the track.

Cevabı ve açıklamayı göster

Cevap: Incorporating steel ball bearings or roller wheels between the door and the base.

Cevap

Incorporating steel ball bearings or roller wheels between the door and the base.

The correct answer identifies that converting sliding friction into rolling friction (by using wheels or bearings) is one of the most effective mechanical methods to reduce resistance. Rolling friction is generally much weaker than sliding friction because the contact surfaces do not grind against each other as they move.

Adım Adım Çözüm

1

Identify the type of friction currently acting on the door.

The door dragging flat against a metal track experiences kinetic (sliding) friction.

Understanding the current state helps identify how to improve the system.

2

Evaluate the options based on mechanical principles to find the best method for reducing resistance.

Adding wheels or ball bearings changes the interaction from sliding to rolling.

Rolling friction is significantly lower than sliding friction for hard materials like steel, making this the most effective mechanical improvement.

Anahtar Kavram

Rolling friction is substantially lower than sliding (kinetic) friction, which is why wheels and bearings are used in mechanical designs to reduce resistance.

Tahmini Süre:45s

Soru 48Soru →

If a hockey puck is sliding across a perfectly frictionless sheet of ice at a constant velocity, a continuous forward force must be applied to it to keep it moving at that velocity.

Doğru

Yanlış

Cevabı ve açıklamayı göster

Cevap: False

Cevap

False

The statement is false because it contradicts Newton's First Law of motion. The law dictates that a moving object naturally maintains its velocity unless an external force intervenes. Since the surface is frictionless and there is no resistance to overcome, no continuous pushing force is needed to sustain the puck's motion.

Adım Adım Çözüm

1

Analyze the environmental conditions described in the scenario.

The scenario specifies a 'perfectly frictionless sheet of ice', meaning there is zero opposing force of friction acting on the sliding hockey puck.

Identifying all external forces (or the lack thereof) is necessary before applying the laws of motion.

2

Apply Newton's First Law of motion to the isolated puck.

Because there are no unbalanced external forces acting on the puck along the horizontal plane, its state of motion will not change.

Newton's First Law states that an object in motion stays in motion with the same speed and in the same direction unless acted upon by a net external force.

3

Determine if a forward force is required based on the law.

A forward force would cause the puck to accelerate. Since it is moving at a 'constant velocity', no such forward force is needed.

Force is required to change velocity (accelerate or decelerate), not to maintain it in a frictionless environment.

Anahtar Kavram

In the absence of opposing forces like friction, an object moving at a constant velocity requires absolutely no applied force to maintain its state of motion.

Soru 49Soru →

A cargo crate has a weight of $4,900 \text{ N}$ on Earth (where $g = 9.8 \text{ m/s}^2$ ). It is sliding across a frictionless floor at a velocity of $12 \text{ m/s}$ when it hits a padded wall. If the crate comes to a complete stop in $0.6 \text{ s}$ , what is the average impact force exerted on the crate during this collision?

98,000 \text{ N}

10,000 \text{ N}

3,600 \text{ N}

25 \text{ N}

Cevabı ve açıklamayı göster

Cevap: $10,000 \text{ N}$

Cevap

The average impact force is

10,000 \text{ N}

.

To find the average impact force, we use the impulse-momentum theorem (

F\Delta t = m\Delta v

) or Newton's second law (

F = ma

). First, we must convert the weight to mass by dividing by the acceleration due to gravity:

4,900 \text{ N} / 9.8 \text{ m/s}^2 = 500 \text{ kg}

. Next, we calculate the acceleration by dividing the change in velocity by the impact time:

12 \text{ m/s} / 0.6 \text{ s} = 20 \text{ m/s}^2

. Multiplying the mass by the acceleration gives the force:

500 \text{ kg} \times 20 \text{ m/s}^2 = 10,000 \text{ N}

.

Adım Adım Çözüm

1

Calculate the mass of the crate from its weight.

m = \frac{W}{g} = \frac{4,900 \text{ N}}{9.8 \text{ m/s}^2} = 500 \text{ kg}

Newton's laws and momentum calculations require mass, not weight.

2

Calculate the crate's change in velocity.

\Delta v = 12 \text{ m/s} - 0 \text{ m/s} = 12 \text{ m/s}

The crate comes to a complete stop, so the total change in velocity is its initial velocity.

3

Calculate the crate's acceleration (or deceleration) during the impact.

a = \frac{\Delta v}{\Delta t} = \frac{12 \text{ m/s}}{0.6 \text{ s}} = 20 \text{ m/s}^2

Acceleration is the change in velocity divided by the time it takes to change.

4

Calculate the average impact force using Newton's Second Law.

F = m \times a = 500 \text{ kg} \times 20 \text{ m/s}^2 = 10,000 \text{ N}

Force equals mass times acceleration. (Alternatively, impulse

F\Delta t = \Delta p

yields the same result:

F = \frac{500 \times 12}{0.6} = 10,000 \text{ N}

).

Anahtar Kavram

The impulse-momentum theorem and the distinction between mass and weight.

Soru 50Soru →

A maintenance team needs to move a heavy steel generator across a flat concrete floor. Arrange the following methods in order from the HIGHEST amount of frictional resistance to the LOWEST amount of frictional resistance.

Öğeleri doğru sıraya koymak için sürükleyin

Cevabı ve açıklamayı göster

Cevap

The correct order from highest to lowest resistance is: dragging directly on dry concrete, sliding with industrial lubricant, and placing on steel rollers.

Dry sliding friction creates the most resistance due to direct, rough surface-to-surface contact. Lubricating the surface reduces this resistance by creating a fluid film between the objects, lowering the friction coefficient. However, rolling friction (using rollers) is the most efficient method and creates the absolute least resistance, as it prevents the surfaces from scraping against each other entirely.

Adım Adım Çözüm

1

Identify the primary type of friction acting in each of the three moving methods.

Dragging directly involves dry sliding friction; using lubricant involves fluid or mixed friction; using steel rollers involves rolling friction.

Recognizing the physical mechanism at the contact surface is the first step in comparing resistance levels.

2

Compare the relative magnitudes of these different types of friction.

Dry sliding friction provides the greatest resistance due to interlocking surface irregularities. Lubrication reduces this contact, lowering resistance. Rolling friction provides the least resistance as sliding is eliminated.

Fundamental mechanical principles state that, for a given load, dry kinetic friction is generally greater than fluid friction, which in turn is greater than rolling friction.

3

Order the methods from highest frictional resistance to lowest.

Highest is dry dragging, middle is lubricated sliding, lowest is steel rollers.

This matches the sequence requirements specified in the question stem.

Anahtar Kavram

Types and relative magnitudes of mechanical friction

Tahmini Süre:45s

Soru 51Soru →

An arresting gear system is used to stop a $12,000 \text{ kg}$ aircraft landing on a flight deck. The aircraft touches down with a velocity of $144 \text{ km/h}$ and is brought to a complete stop in $2.0 \text{ seconds}$ by the arresting wire. Assuming a constant deceleration, what is the magnitude of the average net braking force applied to the aircraft?

600 \text{ N}

864,000 \text{ N}

240,000 \text{ N}

2,352,000 \text{ N}

Cevabı ve açıklamayı göster

Cevap: $240,000 \text{ N}$

Cevap

The correct magnitude of the net braking force is

240,000 \text{ N}

.

The correct answer accurately calculates the force by first converting the velocity from km/h to m/s (

144 \text{ km/h} \times \frac{1000 \text{ m}}{3600 \text{ s}} = 40 \text{ m/s}

). It then finds the magnitude of acceleration (

a = \frac{\Delta v}{t} = \frac{40 \text{ m/s}}{2.0 \text{ s}} = 20 \text{ m/s}^2

) and applies Newton's Second Law (

F = m \times a = 12,000 \text{ kg} \times 20 \text{ m/s}^2 = 240,000 \text{ N}

).

Adım Adım Çözüm

1

Convert the initial velocity from km/h to m/s.

144 \text{ km/h} \times \left(\frac{1000 \text{ m}}{3600 \text{ s}}\right) = 40 \text{ m/s}

Standard SI units (meters and seconds) are required to correctly calculate force in Newtons.

2

Calculate the magnitude of acceleration (deceleration) using the change in velocity over time.

a = \frac{40 \text{ m/s}}{2.0 \text{ s}} = 20 \text{ m/s}^2

Acceleration is defined as the rate of change of velocity.

3

Apply Newton's Second Law to find the average net braking force.

F = 12,000 \text{ kg} \times 20 \text{ m/s}^2 = 240,000 \text{ N}

Newton's Second Law states that force equals mass times acceleration (

F = ma

).

Anahtar Kavram

Newton's Second Law (F=ma) and Kinematics

Soru 52Soru →

A naval torpedo with a mass of $1,200 \text{ kg}$ is fired from a submarine. If the propulsion system generates a constant net forward force of $6,000 \text{ N}$ , what is the forward acceleration of the torpedo?

0.2 \text{ m/s}^2

0.5 \text{ m/s}^2

5.0 \text{ m/s}^2

50.0 \text{ m/s}^2

Cevabı ve açıklamayı göster

Cevap: $5.0 \text{ m/s}^2$

Cevap

The correct answer is

5.0 \text{ m/s}^2

.

According to Newton's Second Law (

F = ma

), acceleration is calculated by dividing the net force by the mass. Dividing

6,000 \text{ N}

by

1,200 \text{ kg}

yields

5.0 \text{ m/s}^2

.

Adım Adım Çözüm

1

Identify the given values from the problem statement.

Mass (

m

) =

1,200 \text{ kg}

, Net Force (

F

) =

6,000 \text{ N}

.

Extracting the known variables is necessary to apply the correct physics formula.

2

Apply Newton's Second Law of Motion.

The formula is

F = ma

. Rearranging to solve for acceleration gives

a = \frac{F}{m}

.

Newton's Second Law relates force, mass, and acceleration.

3

Substitute the values into the formula and solve.

a = \frac{6000}{1200} = 5.0 \text{ m/s}^2

.

Dividing the net force by the mass computes the resulting acceleration.

Anahtar Kavram

Newton's Second Law states that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass (

F = ma

).

Soru 53Soru →

A heavy winch is dragging a $200\text{ kg}$ rectangular steel block across a flat, horizontal concrete surface at a constant velocity of $5\text{ m/s}$ . The coefficient of kinetic friction between the steel and the concrete is $0.4$ . (Assume gravitational acceleration $g = 10\text{ m/s}^2$ ). What is the approximate kinetic frictional force opposing the block's motion, and how would this force change if the block were turned to slide on a face with only half the original surface area?

800\text{ N}

; the frictional force would remain exactly the same.

80\text{ N}

; the frictional force would remain exactly the same.

800\text{ N}

; the frictional force would be halved.

1,000\text{ N}

; the frictional force would remain exactly the same.

Cevabı ve açıklamayı göster

Cevap: $800\text{ N}$ ; the frictional force would remain exactly the same.

Cevap

The kinetic frictional force is

800\text{ N}

, and it would remain exactly the same if the surface area were halved.

The correct answer accurately calculates the normal force by multiplying mass and gravity (

200 \times 10 = 2000\text{ N}

), then applies the friction coefficient (

2000 \times 0.4 = 800\text{ N}

). Furthermore, it correctly applies the principle that sliding friction is unaffected by the size of the contact area, so the force remains constant regardless of which face the block slides on.

Adım Adım Çözüm

1

Calculate the weight (which equals the normal force) of the block.

W = mg = 200\text{ kg} \times 10\text{ m/s}^2 = 2000\text{ N}

. Since the surface is horizontal, the normal force

N = 2000\text{ N}

.

Kinetic friction is directly proportional to the normal force pressing the surfaces together.

2

Calculate the kinetic frictional force.

F_k = \mu_k \times N = 0.4 \times 2000\text{ N} = 800\text{ N}

.

The formula for kinetic friction requires multiplying the normal force by the coefficient of kinetic friction.

3

Evaluate the effect of changing the surface area.

The frictional force remains

800\text{ N}

.

Amontons' Second Law of Friction states that the force of friction is independent of the apparent area of contact. The pressure increases on the smaller area, but the total normal force remains unchanged.

Anahtar Kavram

Kinetic friction depends solely on the normal force and the materials in contact (coefficient of friction), and is completely independent of the contact surface area and velocity.

Soru 54Soru →

Match each real-world circular motion scenario with the correct mechanical principle or force description that governs it.

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Cevabı ve açıklamayı göster

Cevap

The correct matches align specific real-world mechanical scenarios with the physical principles governing circular motion, inertia, and force vectors.

In circular motion, centripetal force is the required net inward force that keeps an object moving in a curve. The source of this force varies depending on the scenario (e.g., friction on a flat road, or normal force at the bottom of a loop). If this force is removed, the object follows a tangential path due to inertia. The outward 'centrifugal' sensation is not a true force, but rather the effect of inertia resisting a change in direction.

Adım Adım Çözüm

1

Analyze the snapped cable scenario (left_1).

Matches with tangential path (right_2).

When a centripetal force is suddenly removed, inertia dictates that the object travels straight along the tangent line of the curve.

2

Analyze the flat curve scenario (left_2).

Matches with static friction (right_1).

Without banking to provide a normal force component, friction is the only lateral force capable of directing the vehicle toward the center of curvature.

3

Analyze the passenger turning scenario (left_3).

Matches with inertia and fictitious outward force (right_4).

The sensation of being thrown outward is actually the body's inertia attempting to travel straight while the vehicle accelerates inward.

4

Analyze the vertical dive pull-out scenario (left_4).

Matches with normal force exceeding gravity (right_3).

To create a net upward (center-pointing) force at the bottom of a dive, the upward normal force must support the aircraft's weight and provide the additional centripetal force.

Anahtar Kavram

Circular Motion and Centripetal Force

Soru 55Soru →

Match each physical concept or measuring instrument to its correct characteristic or function regarding mass and weight.

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Cevabı ve açıklamayı göster

Cevap

Mass pairs with the constant fundamental property; Weight pairs with the gravity-dependent force; Double-pan balance pairs with the consistent standard-comparison device; Spring scale pairs with the coil-based device.

The correct pairings accurately reflect that mass is an invariant scalar quantity measured consistently by a balance, while weight is a vector force that depends on local gravity and is measured by a spring scale.

Adım Adım Çözüm

1

Distinguish between the conceptual definitions of mass and weight.

Mass is identified as a constant amount of matter, whereas weight is the variable force of gravity acting on that matter.

To correctly match the physical properties with their fundamental definitions.

2

Determine the operational principles of the two measuring instruments.

A double-pan balance compares masses directly and works consistently regardless of local gravity, whereas a spring scale measures downward force (weight) via coil stretch, which varies with gravity.

To correctly pair the measuring devices with their functional characteristics across different gravitational fields.

Anahtar Kavram

Mass is an invariant property measured by comparing it to known standards (using a balance), while weight is a location-dependent force measured by its effect on a spring (using a spring scale).

Soru 56Soru →

Match each physical scenario with the magnitude of its resulting acceleration. Apply Newton's Second Law of Motion ( $F=ma$ ) and ensure you calculate the net force for each situation.

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Cevabı ve açıklamayı göster

Cevap

The correct matches are: Transport vehicle maps to 2.0 m/s², Hovercraft maps to 3.0 m/s², Hoisted payload maps to 6.0 m/s², and Descending elevator maps to 4.0 m/s².

Each correct match is derived by first identifying all acting forces on the object, determining the net force (

F_{net}

), and then dividing by the mass (

a = F_{net}/m

). For horizontal motion, opposing forces (friction, drag) are subtracted from applied thrust. For vertical motion, the object's weight (

mg

) must be calculated and subtracted from the cable tension.

Adım Adım Çözüm

1

Calculate the acceleration for the transport vehicle.

Net force = 12,000 N - 2,000 N - 2,000 N = 8,000 N. Acceleration = 8,000 N / 4,000 kg = 2.0 m/s².

Forces acting in the opposite direction of motion (drag and friction) must be subtracted from the forward thrust.

2

Calculate the acceleration for the hovercraft.

Net force = (2 * 3,000 N) - 1,500 N = 4,500 N. Acceleration = 4,500 N / 1,500 kg = 3.0 m/s².

The total thrust from both propellers must be combined before subtracting the opposing water current.

3

Calculate the acceleration for the hoisted payload.

Weight = 500 kg * 10 m/s² = 5,000 N. Net upward force = 8,000 N - 5,000 N = 3,000 N. Acceleration = 3,000 N / 500 kg = 6.0 m/s².

In vertical motion, the downward force of gravity (weight) must be calculated and subtracted from the upward tension to find the net force.

4

Calculate the acceleration for the descending elevator.

Weight = 800 kg * 10 m/s² = 8,000 N. Net downward force = 8,000 N - 4,800 N = 3,200 N. Acceleration = 3,200 N / 800 kg = 4.0 m/s².

Because the elevator descends, the downward gravitational force exceeds the upward tension. Net force is weight minus tension.

Anahtar Kavram

Newton's Second Law of Motion (

F_{net} = ma

)

Soru 57Soru →

A mechanic needs to move a heavy steel block across a flat concrete floor. Which of the following actions will successfully decrease the frictional resistance between the block and the floor?

Turning the block so it rests on its narrowest side to reduce the contact surface area

Placing round steel pipes underneath the block to act as rollers

Pressing downward on the top of the block while moving it to decrease its mass

Pushing the block with a sudden strike to eliminate the floor's opposing reaction force

Cevabı ve açıklamayı göster

Cevap: Placing round steel pipes underneath the block to act as rollers

Cevap

Placing round steel pipes underneath the block to act as rollers.

Rolling friction is significantly lower than sliding (kinetic) friction. By placing round steel pipes under the heavy block, the sliding motion is converted into a rolling motion, which drastically reduces the physical effort and resistance required to move the object.

Adım Adım Çözüm

1

Identify the type of friction currently acting on the block.

The block is sliding directly across the floor, so sliding (kinetic) friction is present.

Understanding the current resistance is necessary to evaluate ways to reduce it.

2

Evaluate the physical effect of each proposed action.

Changing surface area has no effect on friction magnitude. Pressing down increases friction. A sudden strike cannot eliminate reaction forces. Using pipes changes the friction type entirely.

Applying physical laws to each option isolates the effective method.

3

Compare the magnitude of sliding friction to rolling friction.

Rolling friction is significantly lower than sliding friction for heavy objects on hard surfaces.

This confirms that using pipes as rollers is the mechanically correct way to decrease resistance.

Anahtar Kavram

Friction and Resistance (Rolling vs. Sliding Friction)

Tahmini Süre:45s

Soru 58Soru →

An astronaut floating motionless in space throws a heavy wrench directly forward. As a result, the astronaut is pushed backward. According to Newton's Third Law of Motion, what causes the astronaut to move backward?

The wrench exerts a backward force on the astronaut that is equal to the forward force applied to the wrench.

The astronaut's inertia acts in the opposite direction to resist the forward motion of the wrench.

The heavy mass of the astronaut generates a larger backward force than the wrench's forward force.

The sudden removal of the wrench's weight creates an imbalance that propels the astronaut backward.

Cevabı ve açıklamayı göster

Cevap: The wrench exerts a backward force on the astronaut that is equal to the forward force applied to the wrench.

Cevap

The wrench exerts an equal and opposite backward force on the astronaut.

Newton's Third Law of Motion states that for every action, there is an equal and opposite reaction. These forces always act on two different interacting bodies. When the astronaut (Body 1) applies a forward force to the wrench (Body 2), the wrench simultaneously applies a backward force of exactly the same magnitude to the astronaut. This equal and opposite push is what causes the astronaut to move backward.

Adım Adım Çözüm

1

Identify the initial action force described in the scenario.

The action force is the astronaut's hand pushing the heavy wrench forward.

To apply Newton's Third Law, the first interacting body and its applied force must be defined.

2

Apply Newton's Third Law of Motion to find the reaction force.

For the forward force on the wrench, there must be an equal and opposite backward force.

Newton's Third Law dictates that every action has an equal and opposite reaction occurring on the other interacting body.

3

Determine which object applies this reaction force to the astronaut.

The wrench applies the backward force onto the astronaut.

Forces in a Third Law pair always act on opposite objects: Astronaut pushes Wrench, therefore Wrench pushes Astronaut.

Anahtar Kavram

Newton's Third Law (Action/Reaction)

Tahmini Süre:45s

Soru 59Soru →

Match each type of frictional resistance to its correct mechanical description or real-world example.

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Cevabı ve açıklamayı göster

Cevap

Static Friction matches with keeping a stationary object from moving; Kinetic Friction matches with scraping resistance between flat surfaces; Rolling Friction matches with ball bearings turning; Fluid Friction matches with aerodynamic drag.

Each classification of friction applies to a distinct mechanical interaction: static for preventing initial movement, kinetic for active sliding, rolling for rotating circular objects, and fluid for motion through gases or liquids.

Adım Adım Çözüm

1

Analyze the definition of static friction.

Matches with the resistance keeping a stationary heavy object from moving.

The term 'static' refers to objects that are at rest relative to each other.

2

Analyze the definition of kinetic or sliding friction.

Matches with the scraping resistance between two flat solid surfaces like brake pads.

The term 'kinetic' applies to objects that are currently in relative sliding motion.

3

Analyze the definition of rolling friction.

Matches with the minimal resistance of ball bearings turning.

Rolling friction specifically applies to round objects rotating over a surface.

4

Analyze the definition of fluid friction.

Matches with the aerodynamic drag force on a moving vehicle.

Air is a fluid, and drag is the fluid friction acting against moving objects.

Anahtar Kavram

Understanding the fundamental types of friction and how to identify them in practical mechanical scenarios.

Soru 60Soru →

Using Newton's Second Law ( $F = ma$ ), match each mechanical scenario with its correct missing value (force, mass, or acceleration).

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Cevabı ve açıklamayı göster

Cevap

The matches are calculated by rearranging

F = ma

to solve for the missing variable, factoring in net force where applicable, and applying direct proportionality.

Newton's Second Law states that net force equals mass times acceleration (

F = ma

). By determining the net force and algebraically rearranging the formula, or by applying proportional reasoning rules, each scenario can be correctly matched to its missing value.

Adım Adım Çözüm

1

Calculate the net force where opposing forces are present.

Subtract friction from the applied force to find the true net force acting on the object.

Newton's Second Law only applies to the net force, not just the applied force.

2

Apply Newton's Second Law (

F = ma

) or its rearranged forms.

Use

F = ma

for force,

m = \frac{F}{a}

for mass, and

a = \frac{F}{m}

for acceleration.

These equations isolate the missing variable for the first three scenarios.

3

Apply proportional reasoning for the final scenario.

Recognize that tripling the force triples the acceleration.

Since

a = \frac{F}{m}

, acceleration and force are directly proportional when mass is constant.

Anahtar Kavram

Newton's Second Law

Tahmini Süre:1m 30s

Force, Mass, and Motion

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