1.Easy
A 1 kg ball is dropped from rest from a height of 4 m. Ignore air resistance. Find its speed v just before it hits the ground.
m = 1 kgh = 4 mg = 9.81 m/s²
v = m/s
Work & energy worksheet with answers
2.Easy
A 5 kg ball is dropped from rest from a height of 46 m. Ignore air resistance. Find its speed v just before it hits the ground.
m = 5 kgh = 46 mg = 9.81 m/s²
v = m/s
3.Medium
A 1 kg block slides 19 m down a slope at 30° to the horizontal, with a coefficient of kinetic friction of 0.25. Find the work Wf done against friction.
m = 1 kgθ = 30°μ = 0.25d = 19 mg = 9.81 m/s²
Wf = J
4.Medium
A block slides from rest down a slope at 40° to the horizontal. The coefficient of kinetic friction is 0.2. Find its speed v after it has slid 11 m along the slope.
θ = 40°μ = 0.2d = 11 mg = 9.81 m/s²
v = m/s
5.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 2.5 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 = 2.5 kgh = 4.5 mL = 2.5 mμ = 0.2k = 5000 N/mg = 9.81 m/s²
x = cm
6.Hard
A 20 kg block starts from rest at the bottom of a 25° slope and is pulled up the slope by a constant force of 205 N parallel to the slope. The coefficient of kinetic friction is 0.25. Find the speed v of the block after it has moved 8 m up the slope.
m = 20 kgF = 205 Nθ = 25°μ = 0.25d = 8 mg = 9.81 m/s²
v = m/s
Answer key
- 1. v = 8.859 m/s
- 2. v = 30.04 m/s
- 3. Wf = 40.35 J
- 4. v = 10.28 m/s
- 5. x = 19.81 cm
- 6. v = 7.881 m/s
Full step-by-step solutions: practise this topic on examproblems.com.