Work, energy and conservation of energyEdexcel International A Level Physics: Mind map

Exam questions on Work, energy and conservation of energy

1. A student pulls a sledge of mass 12 kg along level ground with a rope. The tension in the rope is 50 N and the rope makes an angle of 30° above the horizontal. The sledge moves 8.0 m from rest. A constant frictional force of 30 N opposes the motion.
   Calculate the speed of the sledge after it has moved 8.0 m.2 marks
2. A ball of mass 0.15 kg is thrown vertically upwards from ground level with an initial speed of 14 m s⁻¹. In a first model, air resistance is ignored. The acceleration of free fall is 9.81 m s⁻².
   In practice the ball reaches a maximum height of only 9.0 m. Calculate the energy dissipated by air resistance as the ball rises.2 marks
3. A child of mass 30 kg slides from rest down a straight playground slide of length 4.0 m. The top of the slide is 2.5 m above the bottom. The child reaches the bottom at a speed of 5.0 m s⁻¹.
   Calculate the energy dissipated as the child slides down the slide.3 marks