1.Easy
A 2 kg ball is dropped from rest from a height of 29 m. Ignore air resistance. Find its speed v just before it hits the ground.
m = 2 kgh = 29 mg = 9.81 m/s²
v = m/s
Work & energy worksheet with answers
2.Easy
A 0.5 kg ball is dropped from rest from a height of 11 m. Ignore air resistance. Find its speed v just before it hits the ground.
m = 0.5 kgh = 11 mg = 9.81 m/s²
v = m/s
3.Medium
A car travelling at 110 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 0.6. Find the stopping distance d.
v = 110 km/hμ = 0.6g = 9.81 m/s²
d = m
4.Medium
A 2 kg block slides 9 m down a slope at 35° to the horizontal, with a coefficient of kinetic friction of 0.3. Find the work Wf done against friction.
m = 2 kgθ = 35°μ = 0.3d = 9 mg = 9.81 m/s²
Wf = J
5.Hard
A 4 kg block is released from rest at height 1 m on a smooth ramp. At the bottom it crosses a rough horizontal strip 2 m long (μ = 0.2) and then runs onto a spring (k = 5000 N/m) on a smooth surface. Find the maximum compression x of the spring.
m = 4 kgh = 1 mL = 2 mμ = 0.2k = 5000 N/mg = 9.81 m/s²
x = cm
6.Hard
A spring of stiffness 2000 N/m at the bottom of a 15° slope is compressed by 15 cm against a 0.5 kg block and released. The coefficient of kinetic friction between block and slope is 0.2. How far d up the slope does the block travel from the release point before it stops? (Ignore the short distance over which the spring pushes, i.e. take friction and gravity over the whole distance d.)
m = 0.5 kgk = 2000 N/mx = 15 cmθ = 15°μ = 0.2g = 9.81 m/s²
d = m
Answer key
- 1. v = 23.85 m/s
- 2. v = 14.69 m/s
- 3. d = 79.31 m
- 4. Wf = 43.39 J
- 5. x = 9.704 cm
- 6. d = 10.15 m
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