Question

Difficulty: MediumGravity and Free Fall

Arrange the following stages of a skydiver's jump in chronological order, starting from the moment they step out of a hovering helicopter until just before they touch the ground.

  1. 1The skydiver experiences maximum downward acceleration, with gravity being the only significant acting force.
  2. 2Downward velocity increases, causing air resistance to build up and the net downward acceleration to decrease.
  3. 3Air resistance perfectly balances the force of gravity, resulting in zero acceleration and a constant falling speed.
  4. 4The parachute is deployed, drastically increasing air resistance and creating a net upward force that slows the descent.
  5. 5The forces of gravity and air resistance balance once again, establishing a new, slower constant falling speed.

Answer

The correct sequence follows the progression of forces: maximum initial acceleration, decreasing acceleration as drag builds, first terminal velocity, rapid deceleration upon parachute deployment, and finally a second, slower terminal velocity.
A falling object initially accelerates under gravity alone. As its velocity increases, air resistance grows until it perfectly opposes gravity, resulting in a constant terminal velocity. Deploying a parachute drastically increases the surface area, creating a temporary net upward force that slows the fall until a new, slower terminal velocity is established for a safe landing.

Step-by-Step Solution

1
Analyze the initial phase of the jump.
Identify that at the moment of the jump, velocity is zero.
Without velocity, there is no air resistance. Gravity is the only force, causing maximum acceleration.
2
Evaluate the effect of increasing speed.
Determine that accelerating downwards causes air resistance to grow.
Air drag is proportional to velocity. As drag increases, it opposes gravity, reducing the net downward acceleration.
3
Identify the first equilibrium state.
Recognize that terminal velocity is reached when air resistance equals gravity.
When the net force is zero, Newton's first law dictates that acceleration stops and velocity becomes constant.
4
Assess the impact of parachute deployment.
Identify that the parachute causes a massive, sudden increase in air drag.
The drag force temporarily exceeds the gravitational force, creating an upward net force that rapidly slows the downward fall.
5
Determine the final state before landing.
Conclude that a new equilibrium is reached at a much slower speed.
As the skydiver slows down, the drag on the parachute decreases until it balances gravity once more.

Key Concept

The relationship between gravity, air resistance, and terminal velocity during free fall.
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