Work & energy worksheet with answers

Free printable Work & energy worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

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1.Easy

A hoist lifts a 50 kg load at constant speed through a height of 11 m in 30 s. Find the average power P it delivers to the load, in W.

m = 50 kgh = 11 mt = 30 sg = 9.81 m/s²

P = W

2.Easy

A crate is pulled 20 m along a level floor by a rope that makes 60° with the horizontal. The tension in the rope is 120 N. Find the work W done by the rope on the crate.

F = 120 Nd = 20 mθ = 60°

W = J

3.Medium

A 4 kg block slides 3 m down a slope at 35° to the horizontal, with a coefficient of kinetic friction of 0.1. Find the work W_f done against friction.

m = 4 kgθ = 35°μ = 0.1d = 3 mg = 9.81 m/s²

W_f = J

4.Medium

A block slides from rest down a slope at 30° to the horizontal. The coefficient of kinetic friction is 0.25. Find its speed v after it has slid 16 m along the slope.

θ = 30°μ = 0.25d = 16 mg = 9.81 m/s²

v = m/s

5.Hard

A 2.5 kg block is released from rest at height 2 m on a smooth ramp. At the bottom it crosses a rough horizontal strip 2.5 m long (μ = 0.15) and then runs onto a spring (k = 2500 N/m) on a smooth surface. Find the speed v of the block when it reaches the spring.

m = 2.5 kgh = 2 mL = 2.5 mμ = 0.15k = 2500 N/mg = 9.81 m/s²

v = m/s

6.Hard

A 1 kg cart is released from rest at a height of 20 m on a smooth track that leads into a vertical circular loop of radius 5 m. Find the normal force N the track exerts on the cart at the top of the loop.

m = 1 kgh = 20 mR = 5 mg = 9.81 m/s²

N = N

Answer key

1. P = 179.8 W
2. W = 1200 J
3. W_f = 9.643 J
4. v = 9.434 m/s
5. v = 5.646 m/s
6. N = 29.43 N

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