1.Easy
A 1 kg ball is dropped from rest from a height of 24 m. Ignore air resistance. Find its speed v just before it hits the ground.
m = 1 kgh = 24 mg = 9.81 m/s²
v = m/s
Work & energy worksheet with answers
2.Easy
A crate is pulled 4 m along a level floor by a rope that makes 50° 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 = 4 mθ = 50°
W = J
3.Medium
A block slides from rest down a slope at 25° to the horizontal. The coefficient of kinetic friction is 0.1. Find its speed v after it has slid 11 m along the slope.
θ = 25°μ = 0.1d = 11 mg = 9.81 m/s²
v = m/s
4.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 0.7. Find the stopping distance d.
v = 60 km/hμ = 0.7g = 9.81 m/s²
d = m
5.Hard
An 8 kg block starts from rest at the bottom of a 35° slope and is pulled up the slope by a constant force of 95 N parallel to the slope. The coefficient of kinetic friction is 0.3. Find the speed v of the block after it has moved 6 m up the slope.
m = 8 kgF = 95 Nθ = 35°μ = 0.3d = 6 mg = 9.81 m/s²
v = m/s
6.Hard
A 5 kg block rests on a rough horizontal table (μ = 0.15). A light string runs from it over a smooth pulley at the edge of the table to a hanging 1 kg block. The system is released from rest. Find the speed v of the blocks after the hanging block has dropped 3 m.
m1 = 5 kgm2 = 1 kgμ = 0.15d = 3 mg = 9.81 m/s²
v = m/s
Answer key
- 1. v = 21.7 m/s
- 2. W = 411.4 J
- 3. v = 8.465 m/s
- 4. d = 20.23 m
- 5. v = 6.786 m/s
- 6. v = 1.566 m/s
Full step-by-step solutions: practise this topic on examproblems.com.