1) A small metal sphere of mass m is moving through a viscous liquid of height h. When it reaches a constant downward velocity v, which of the following describes the changes with time in the kinetic energy and gravitational potential energy of the sphere?

2) A motorist travelling at 10 m s^–1 can bring his car to rest in a distance of 10 m. If he had been travelling at 30 m s^–1, in what distance could he bring the car to rest using the
same braking force?

3) A small emergency generator supplies 4.32 × 10⁸ J of electrical energy in 24 hours. What
is the average power output of the generator?

4) A crane lifts a weight of 1000 N through a vertical height of 30 m. It uses 60 000 J of energy. What is the efficiency of the crane?

5) A box of mass 2 kg is being pushed horizontally along a smooth surface by a 10 N force for 6 m.

What is the work done on the box by the 10 N force?