1.Easy
A crate is pulled 16 m along a level floor by a rope that makes 15° with the horizontal. The tension in the rope is 120 N. Find the work W done by the rope on the crate.
F = 120 Nd = 16 mθ = 15°
W = J
Work & energy worksheet with answers
2.Easy
A small ball hangs on a light string of length 0.5 m. It is pulled aside until the string makes 50° with the vertical and released from rest. Ignoring air resistance, find its speed v at the lowest point.
L = 0.5 mθ = 50°g = 9.81 m/s²
v = m/s
3.Medium
A 1 kg block slides 12 m down a slope at 25° to the horizontal, with a coefficient of kinetic friction of 0.3. Find the work Wf done against friction.
m = 1 kgθ = 25°μ = 0.3d = 12 mg = 9.81 m/s²
Wf = J
4.Medium
A block slides from rest down a slope at 30° to the horizontal. The coefficient of kinetic friction is 0.2. Find its speed v after it has slid 4 m along the slope.
θ = 30°μ = 0.2d = 4 mg = 9.81 m/s²
v = m/s
5.Hard
A 1 kg block is released from rest at height 2.5 m on a smooth ramp. At the bottom it crosses a rough horizontal strip 4.5 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 = 2.5 mL = 4.5 mμ = 0.25k = 1500 N/mg = 9.81 m/s²
x = cm
6.Hard
A 2 kg block is released from rest at height 1.5 m on a smooth ramp. At the bottom it crosses a rough horizontal strip 3.5 m long (μ = 0.2) and then runs onto a spring (k = 2000 N/m) on a smooth surface. Find the maximum compression x of the spring.
m = 2 kgh = 1.5 mL = 3.5 mμ = 0.2k = 2000 N/mg = 9.81 m/s²
x = cm
Answer key
- 1. W = 1855 J
- 2. v = 1.872 m/s
- 3. Wf = 32.01 J
- 4. v = 5.064 m/s
- 5. x = 13.41 cm
- 6. x = 12.53 cm
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