1.Easy
A crate is pulled 2 m along a level floor by a rope that makes 15° with the horizontal. The tension in the rope is 110 N. Find the work W done by the rope on the crate.
F = 110 Nd = 2 mθ = 15°
W = J
Work & energy worksheet with answers
2.Easy
A 10 kg ball is dropped from rest from a height of 20 m. Ignore air resistance. Find its kinetic energy Ek just before it hits the ground.
m = 10 kgh = 20 mg = 9.81 m/s²
Ek = J
3.Medium
A block slides from rest down a slope at 35° to the horizontal. The coefficient of kinetic friction is 0.1. Find its speed v after it has slid 10 m along the slope.
θ = 35°μ = 0.1d = 10 mg = 9.81 m/s²
v = m/s
4.Medium
A block slides from rest down a slope at 15° to the horizontal. The coefficient of kinetic friction is 0.15. Find its speed v after it has slid 20 m along the slope.
θ = 15°μ = 0.15d = 20 mg = 9.81 m/s²
v = m/s
5.Hard
A 2 kg block starts from rest at the bottom of a 15° slope and is pulled up the slope by a constant force of 20 N parallel to the slope. The coefficient of kinetic friction is 0.2. Find the speed v of the block after it has moved 3 m up the slope.
m = 2 kgF = 20 Nθ = 15°μ = 0.2d = 3 mg = 9.81 m/s²
v = m/s
6.Hard
A 2 kg block rests on a rough horizontal table (μ = 0.1). A light string runs from it over a smooth pulley at the edge of the table to a hanging 2 kg block. The system is released from rest. Find the speed v of the blocks after the hanging block has dropped 3 m.
m1 = 2 kgm2 = 2 kgμ = 0.1d = 3 mg = 9.81 m/s²
v = m/s
Answer key
- 1. W = 212.5 J
- 2. Ek = 1962 J
- 3. v = 9.822 m/s
- 4. v = 6.686 m/s
- 5. v = 5.779 m/s
- 6. v = 5.147 m/s
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