1.Easy
A 10 kg ball is dropped from rest from a height of 32 m. Ignore air resistance. Find its kinetic energy Ek just before it hits the ground.
m = 10 kgh = 32 mg = 9.81 m/s²
Ek = J
Work & energy worksheet with answers
2.Easy
A 5 kg ball is dropped from rest from a height of 19 m. Ignore air resistance. Find its speed v just before it hits the ground.
m = 5 kgh = 19 mg = 9.81 m/s²
v = m/s
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 2 kg block slides 10 m down a slope at 30° to the horizontal, with a coefficient of kinetic friction of 0.15. Find the work Wf done against friction.
m = 2 kgθ = 30°μ = 0.15d = 10 mg = 9.81 m/s²
Wf = J
5.Hard
A 4 kg block is released from rest at height 3 m on a smooth ramp. At the bottom it crosses a rough horizontal strip 2.5 m long (μ = 0.2) and then runs onto a spring (k = 2500 N/m) on a smooth surface. Find the maximum compression x of the spring.
m = 4 kgh = 3 mL = 2.5 mμ = 0.2k = 2500 N/mg = 9.81 m/s²
x = cm
6.Hard
A 1 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 = 0.25) and then runs onto a spring (k = 1500 N/m) on a smooth surface. Find the maximum compression x of the spring.
m = 1 kgh = 1 mL = 2 mμ = 0.25k = 1500 N/mg = 9.81 m/s²
x = cm
Answer key
- 1. Ek = 3139 J
- 2. v = 19.31 m/s
- 3. d = 17.7 m
- 4. Wf = 25.49 J
- 5. x = 28.01 cm
- 6. x = 8.087 cm
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