1.Easy
A crate is pulled 16 m along a level floor by a rope that makes 50° with the horizontal. The tension in the rope is 140 N. Find the work W done by the rope on the crate.
F = 140 Nd = 16 mθ = 50°
W = J
Work & energy worksheet with answers
2.Easy
A 5 kg ball is dropped from rest from a height of 31 m. Ignore air resistance. Find its speed v just before it hits the ground.
m = 5 kgh = 31 mg = 9.81 m/s²
v = m/s
3.Medium
A 1800 kg car drives up a 3° slope at a constant 54 km/h. Air resistance and rolling resistance together amount to 200 N. Find the power P the wheels must deliver, in kW.
m = 1800 kgθ = 3°Fr = 200 Nv = 54 km/hg = 9.81 m/s²
P = kW
4.Medium
A 0.5 kg ball hangs on a light string of length 0.5 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 = 0.5 mθ = 40°g = 9.81 m/s²
T = N
5.Hard
A 0.5 kg cart is released from rest at a height of 3.2 m on a smooth track that leads into a vertical circular loop of radius 1 m. Find the normal force N the track exerts on the cart at the top of the loop.
m = 0.5 kgh = 3.2 mR = 1 mg = 9.81 m/s²
N = N
6.Hard
A 4 kg block is released from rest at height 2 m on a smooth ramp. At the bottom it crosses a rough horizontal strip 1 m long (μ = 0.3) and then runs onto a spring (k = 1000 N/m) on a smooth surface. Find the speed v of the block when it reaches the spring.
m = 4 kgh = 2 mL = 1 mμ = 0.3k = 1000 N/mg = 9.81 m/s²
v = m/s
Answer key
- 1. W = 1440 J
- 2. v = 24.66 m/s
- 3. P = 16.86 kW
- 4. T = 7.2 N
- 5. N = 6.867 N
- 6. v = 5.775 m/s
Full step-by-step solutions: practise this topic on examproblems.com.