1.Easy
A 2.5 kg ball is dropped from rest from a height of 50 m. Ignore air resistance. Find its speed v just before it hits the ground.
m = 2.5 kgh = 50 mg = 9.81 m/s²
v = m/s
Work & energy worksheet with answers
2.Easy
A crate is pulled 8 m along a level floor by a rope that makes 40° with the horizontal. The tension in the rope is 160 N. Find the work W done by the rope on the crate.
F = 160 Nd = 8 mθ = 40°
W = J
3.Medium
A car travelling at 60 km/h on a level road brakes hard and skids to a stop with its wheels locked. The coefficient of kinetic friction between the tyres and the road is 0.8. Find the stopping distance d.
v = 60 km/hμ = 0.8g = 9.81 m/s²
d = m
4.Medium
A block slides from rest down a slope at 40° to the horizontal. The coefficient of kinetic friction is 0.3. Find its speed v after it has slid 7 m along the slope.
θ = 40°μ = 0.3d = 7 mg = 9.81 m/s²
v = m/s
5.Hard
An 8 kg block starts from rest at the bottom of a 15° slope and is pulled up the slope by a constant force of 55 N parallel to the slope. The coefficient of kinetic friction is 0.15. Find the speed v of the block after it has moved 7 m up the slope.
m = 8 kgF = 55 Nθ = 15°μ = 0.15d = 7 mg = 9.81 m/s²
v = m/s
6.Hard
A 10 kg cart is released from rest at a height of 6 m on a smooth track that leads into a vertical circular loop of radius 1.5 m. Find the normal force N the track exerts on the cart at the top of the loop.
m = 10 kgh = 6 mR = 1.5 mg = 9.81 m/s²
N = N
Answer key
- 1. v = 31.32 m/s
- 2. W = 980.5 J
- 3. d = 17.7 m
- 4. v = 7.531 m/s
- 5. v = 6.388 m/s
- 6. N = 294.3 N
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