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Zorluk: OrtaInclined Planes

A mechanic needs to move a 150 kg150\text{ kg} engine block onto a storage shelf that is 120 cm120\text{ cm} above the floor. He uses a frictionless inclined plane and applies a constant effort force of 300 N300\text{ N} parallel to the ramp's surface to push the block at a constant speed. Assuming the acceleration due to gravity is 10 m/s210\text{ m/s}^2, what is the required length of the inclined plane, and how does the total work done using the ramp compare to the work required to lift the engine vertically?

  1. 6.0 m6.0\text{ m}; total work done is equal to lifting it verticallyCevap
  2. B
    6.0 m6.0\text{ m}; total work done is less than lifting it vertically
  3. C
    0.6 m0.6\text{ m}; total work done is less than lifting it vertically
  4. D
    600 m600\text{ m}; total work done is equal to lifting it vertically

Cevap

The required length is 6.0 m6.0\text{ m}, and the total work done is equal to the work required to lift the engine vertically.
The weight of the engine block is 1500 N1500\text{ N}. To lift it 1.2 m1.2\text{ m} vertically requires 1800 J1800\text{ J} of work. Using a frictionless ramp, the exact same 1800 J1800\text{ J} of work is performed by applying a smaller 300 N300\text{ N} force over a longer distance (6.0 m6.0\text{ m}). Simple machines change the ratio of force and distance but do not alter the total work done.

Adım Adım Çözüm

1
Calculate the weight of the engine block and convert the height to meters.
Weight = 150 kg×10 m/s2=1500 N150\text{ kg} \times 10\text{ m/s}^2 = 1500\text{ N}. Height = 1.2 m1.2\text{ m}.
Standard SI units (meters) and forces (Newtons) are required for accurate work and energy calculations.
2
Apply the principle of conservation of work (Work Input = Work Output) to solve for the length.
300 N×L=1500 N×1.2 m→300L=1800→L=6.0 m300\text{ N} \times L = 1500\text{ N} \times 1.2\text{ m} \rightarrow 300L = 1800 \rightarrow L = 6.0\text{ m}.
In a frictionless system, the input work done by the effort force over the ramp's length equals the output work needed to lift the object vertically.
3
Compare the total work done in both scenarios.
Work on ramp (300 N×6.0 m=1800 J300\text{ N} \times 6.0\text{ m} = 1800\text{ J}) equals Work lifted vertically (1500 N×1.2 m=1800 J1500\text{ N} \times 1.2\text{ m} = 1800\text{ J}).
Simple machines like inclined planes provide a mechanical advantage by spreading the same amount of work over a longer distance, reducing the required force.

Anahtar Kavram

Ideal Mechanical Advantage and Work Conservation on an Inclined Plane
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