1.Easy
A 5 kg block slides at 3.5 m/s on a smooth horizontal surface into a spring of stiffness 200 N/m. Find the maximum compression x of the spring, in cm.
m = 5 kgv = 3.5 m/sk = 200 N/m
x = cm
Work & energy worksheet with answers
2.Easy
A 0.5 kg ball is dropped from rest from a height of 39 m. Ignore air resistance. Find its speed v just before it hits the ground.
m = 0.5 kgh = 39 mg = 9.81 m/s²
v = m/s
3.Medium
A car travelling at 50 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 = 50 km/hμ = 0.7g = 9.81 m/s²
d = m
4.Medium
A 1 kg block slides 14 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 = 1 kgθ = 30°μ = 0.15d = 14 mg = 9.81 m/s²
Wf = J
5.Hard
A 2.5 kg block is released from rest at height 3 m on a smooth ramp. At the bottom it crosses a rough horizontal strip 3 m long (μ = 0.15) and then runs onto a spring (k = 2500 N/m) on a smooth surface. Find the maximum compression x of the spring.
m = 2.5 kgh = 3 mL = 3 mμ = 0.15k = 2500 N/mg = 9.81 m/s²
x = cm
6.Hard
A 2.5 kg block is released from rest at height 4.5 m on a smooth ramp. At the bottom it crosses a rough horizontal strip 1.5 m long (μ = 0.15) and then runs onto a spring (k = 5000 N/m) on a smooth surface. Find the speed v of the block when it reaches the spring.
m = 2.5 kgh = 4.5 mL = 1.5 mμ = 0.15k = 5000 N/mg = 9.81 m/s²
v = m/s
Answer key
- 1. x = 55.34 cm
- 2. v = 27.66 m/s
- 3. d = 14.05 m
- 4. Wf = 17.84 J
- 5. x = 22.37 cm
- 6. v = 9.158 m/s
Full step-by-step solutions: practise this topic on examproblems.com.