1.Easy
A crate is pulled 12 m along a level floor by a rope that makes 50° with the horizontal. The tension in the rope is 50 N. Find the work W done by the rope on the crate.
F = 50 Nd = 12 mθ = 50°
W = J
Work & energy worksheet with answers
2.Easy
A 10 kg ball is dropped from rest from a height of 31 m. Ignore air resistance. Find its kinetic energy Ek just before it hits the ground.
m = 10 kgh = 31 mg = 9.81 m/s²
Ek = J
3.Medium
A 0.2 kg ball hangs on a light string of length 0.8 m. It is pulled aside until the string makes 60° with the vertical and released from rest. Find the tension T in the string when the ball passes the lowest point.
m = 0.2 kgL = 0.8 mθ = 60°g = 9.81 m/s²
T = N
4.Medium
A 2000 kg car drives up a 4° slope at a constant 54 km/h. Air resistance and rolling resistance together amount to 500 N. Find the power P the wheels must deliver, in kW.
m = 2000 kgθ = 4°Fr = 500 Nv = 54 km/hg = 9.81 m/s²
P = kW
5.Hard
A 1 kg block is released from rest at height 1.5 m on a smooth ramp. At the bottom it crosses a rough horizontal strip 2 m long (μ = 0.15) and then runs onto a spring (k = 5000 N/m) on a smooth surface. Find the maximum compression x of the spring.
m = 1 kgh = 1.5 mL = 2 mμ = 0.15k = 5000 N/mg = 9.81 m/s²
x = cm
6.Hard
A 5 kg block is released from rest at height 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 speed v of the block when it reaches the spring.
m = 5 kgh = 5 mL = 4.5 mμ = 0.25k = 1500 N/mg = 9.81 m/s²
v = m/s
Answer key
- 1. W = 385.7 J
- 2. Ek = 3041 J
- 3. T = 3.924 N
- 4. P = 28.03 kW
- 5. x = 6.862 cm
- 6. v = 8.719 m/s
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