1.Easy
A 0.5 kg ball is dropped from rest from a height of 18 m. Ignore air resistance. Find its speed v just before it hits the ground.
m = 0.5 kgh = 18 mg = 9.81 m/s²
v = m/s
Work & energy worksheet with answers
2.Easy
A 2 kg ball is dropped from rest from a height of 50 m. Ignore air resistance. Find its speed v just before it hits the ground.
m = 2 kgh = 50 mg = 9.81 m/s²
v = m/s
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 2 m along the slope.
θ = 35°μ = 0.1d = 2 mg = 9.81 m/s²
v = m/s
4.Medium
A 1500 kg car drives up a 5° slope at a constant 54 km/h. Air resistance and rolling resistance together amount to 600 N. Find the power P the wheels must deliver, in kW.
m = 1500 kgθ = 5°Fr = 600 Nv = 54 km/hg = 9.81 m/s²
P = kW
5.Hard
A 2.5 kg block is released from rest at height 2.5 m on a smooth ramp. At the bottom it crosses a rough horizontal strip 4.5 m long (μ = 0.3) 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 = 2.5 kgh = 2.5 mL = 4.5 mμ = 0.3k = 1500 N/mg = 9.81 m/s²
v = m/s
6.Hard
A 0.5 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 = 0.15) and then runs onto a spring (k = 1500 N/m) on a smooth surface. Find the maximum compression x of the spring.
m = 0.5 kgh = 3.5 mL = 2.5 mμ = 0.15k = 1500 N/mg = 9.81 m/s²
x = cm
Answer key
- 1. v = 18.79 m/s
- 2. v = 31.32 m/s
- 3. v = 4.392 m/s
- 4. P = 28.24 kW
- 5. v = 4.75 m/s
- 6. x = 14.3 cm
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