1.Easy
A 10 kg ball is dropped from rest from a height of 44 m. Ignore air resistance. Find its speed v just before it hits the ground.
m = 10 kgh = 44 mg = 9.81 m/s²
v = m/s
Work & energy worksheet with answers
2.Easy
A 4 kg ball is dropped from rest from a height of 19 m. Ignore air resistance. Find its kinetic energy Ek just before it hits the ground.
m = 4 kgh = 19 mg = 9.81 m/s²
Ek = J
3.Medium
A 0.5 kg ball hangs on a light string of length 1 m. It is pulled aside until the string makes 40° with the vertical and released from rest. Find the tension T in the string when the ball passes the lowest point.
m = 0.5 kgL = 1 mθ = 40°g = 9.81 m/s²
T = N
4.Medium
A car travelling at 90 km/h on a level road brakes hard and skids to a stop with its wheels locked. The coefficient of kinetic friction between the tyres and the road is 0.5. Find the stopping distance d.
v = 90 km/hμ = 0.5g = 9.81 m/s²
d = m
5.Hard
A 2.5 kg block is released from rest at height 3.5 m on a smooth ramp. At the bottom it crosses a rough horizontal strip 2.5 m long (μ = 0.25) and then runs onto a spring (k = 500 N/m) on a smooth surface. Find the speed v of the block when it reaches the spring.
m = 2.5 kgh = 3.5 mL = 2.5 mμ = 0.25k = 500 N/mg = 9.81 m/s²
v = m/s
6.Hard
A 2.5 kg block is released from rest at height 4 m on a smooth ramp. At the bottom it crosses a rough horizontal strip 5 m long (μ = 0.15) and then runs onto a spring (k = 1500 N/m) on a smooth surface. Find the maximum compression x of the spring.
m = 2.5 kgh = 4 mL = 5 mμ = 0.15k = 1500 N/mg = 9.81 m/s²
x = cm
Answer key
- 1. v = 29.38 m/s
- 2. Ek = 745.6 J
- 3. T = 7.2 N
- 4. d = 63.71 m
- 5. v = 7.51 m/s
- 6. x = 32.6 cm
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