Practice Work in Physics

Use these practice problems to test your method after reviewing the concept explanation and worked examples.

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Quick Recap

The transfer of energy that occurs when a force causes an object to move through a distance in the direction of the force, calculated as W=Fdcos⁡θW = Fd\cos\theta, where θ\theta is the angle between the force and the displacement. Measured in joules (J).

Energy transferred by pushing something through space — force and displacement must both be present.

Showing a random 20 of 50 problems.

Example 1

challenge
A spring is compressed 0.3 m0.3\text{ m} from natural length and then further to 0.5 m0.5\text{ m}. With k=200 N/mk = 200\text{ N/m}, how much extra work is needed for that additional compression?

Example 2

medium
Lifting a 10 kg box up a 4 m vertical wall versus pushing it up a 8 m frictionless ramp to the same 4 m height (g = 9.8). Which path does more work against gravity?

Example 3

easy
How much work lifts a 5 kg mass 2 m at constant speed (g = 9.8)?

Example 4

medium
A net force of 12 N acts on a 4 kg cart over 5 m. Using work, what is the cart's final KE if it started from rest?

Example 5

easy
A force of 20 N acts at 60 degrees to a 5 m displacement. Find the work done.

Example 6

easy
Gravity pulls a 2 kg2\text{ kg} rock down 3 m3\text{ m}. How much work does gravity do (use g=9.8g = 9.8)?

Example 7

easy
A force of 40 N40\text{ N} acts opposite to a 2 m2\text{ m} displacement. What is the work?

Example 8

medium
A 6 kg box is dragged 5 m by a 30 N force at 0 degrees, then friction of 12 N opposes over the same 5 m. Find the total work done on the box.

Example 9

medium
A 30 N30\text{ N} force pulls a sled 12 m12\text{ m} at 45°45° above horizontal. Find the work done by the force (use cos⁡45°≈0.707\cos 45° \approx 0.707).

Example 10

challenge
A variable force on a graph is constant 4 N for the first 3 m, then drops to 2 N for the next 2 m, all along the motion. Find the total work.

Example 11

medium
A spring with k = 200 N/m is compressed 0.1 m. How much work was done on the spring?

Example 12

easy
A horizontal force does 40 J of work moving a crate 8 m horizontally. What was the force?

Example 13

easy
A boy pushes a wall with 80 N80\text{ N} for 30 s30\text{ s}, but the wall does not move. How much work does he do on the wall?

Example 14

easy
A 10 N force pushes a box 4 m in the direction of the force. How much work is done?

Example 15

medium
How much work does gravity do on a 2 kg object that falls 4 m (g = 9.8)?

Example 16

medium
A horizontal 50 N50\text{ N} force pushes a 20 kg20\text{ kg} crate at constant velocity for 8 m8\text{ m}. How much work does friction do?

Example 17

challenge
A 2 kg2\text{ kg} block is pulled along a rough horizontal floor by a rope at 30°30° above horizontal with 20 N20\text{ N} for 6 m6\text{ m}. μk=0.2\mu_k = 0.2. Find the work done by friction (use g=9.8g = 9.8).

Example 18

hard
A 10 kg10\text{ kg} box slides 4 m4\text{ m} down a 37°37° incline with μk=0.25\mu_k = 0.25. Find the work done by friction (use g=9.8g = 9.8, cos⁡37°≈0.8\cos 37° \approx 0.8).

Example 19

easy
A force of 25 N25\text{ N} acts perpendicular to the motion of an object moving 4 m4\text{ m}. Find the work done.

Example 20

challenge
A 2 kg block is pushed 5 m across a floor by a constant 15 N horizontal force against friction of 5 N. Find the block's final speed from rest using work.
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