1.Easy
A crate is pulled 6 m along a level floor by a rope that makes 35° with the horizontal. The tension in the rope is 130 N. Find the work W done by the rope on the crate.
F = 130 Nd = 6 mθ = 35°
W = J
Work & energy worksheet with answers
2.Easy
A 2 kg block slides at 5.5 m/s on a smooth horizontal surface into a spring of stiffness 800 N/m. Find the maximum compression x of the spring, in cm.
m = 2 kgv = 5.5 m/sk = 800 N/m
x = cm
3.Medium
A 1000 kg car drives up a 2° slope at a constant 54 km/h. Air resistance and rolling resistance together amount to 350 N. Find the power P the wheels must deliver, in kW.
m = 1000 kgθ = 2°Fr = 350 Nv = 54 km/hg = 9.81 m/s²
P = kW
4.Medium
A 2 kg block slides 2 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 = 2 mg = 9.81 m/s²
Wf = J
5.Hard
A 4 kg block rests on a rough horizontal table (μ = 0.15). A light string runs from it over a smooth pulley at the edge of the table to a hanging 5 kg block. The system is released from rest. Find the speed v of the blocks after the hanging block has dropped 1.5 m.
m1 = 4 kgm2 = 5 kgμ = 0.15d = 1.5 mg = 9.81 m/s²
v = m/s
6.Hard
A 5 kg block is released from rest at height 2.5 m on a smooth ramp. At the bottom it crosses a rough horizontal strip 5 m long (μ = 0.3) and then runs onto a spring (k = 800 N/m) on a smooth surface. Find the speed v of the block when it reaches the spring.
m = 5 kgh = 2.5 mL = 5 mμ = 0.3k = 800 N/mg = 9.81 m/s²
v = m/s
Answer key
- 1. W = 638.9 J
- 2. x = 27.5 cm
- 3. P = 10.39 kW
- 4. Wf = 5.097 J
- 5. v = 3.793 m/s
- 6. v = 4.429 m/s
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