QU ESTION 2 a) An object of mass 3 kg is dropped from the roof of a two-storey house and reaches the ground with a speed of 10 mfs. Neglecting friction, calculate: i. the kinetic energy of the object when it reaches the ground. ii. the potential energy of the object when it is on the roof. iii. the height of the roof. iv. the total mechanical energy of the object when it is 1 m above the ground. (11 marks) b) A man who has a mass of 80 kg can run up a flight of stairs of 20 steps, in 5 seconds. Given that each step is 20 cm high, how much power does the man use to run up the flight of stairs? {4 marks)