A.3 - Work, Energy and Power

Section b)

a) Show that the average crush force exerted on a car of mass m with impact speed v is equal to mv²/2d

c) i) On a set of axes, sketch graphs to show how the gravitational potential energy and the kinetic energy of the rocket varies as it moves from the ground to its maximum height.

ii) State one assumption, other than ignoring air resistance, that you have made in sketching the above graph.

d) The rocket plus fuel initially have a mass of 0.16 kg. If the initial mass of the fuel is 0.02 kg, calculate the maximum kinetic energy of the rocket when all the fuel has been used.

e) Calculate the power delivered to the rocket by the rocket fuel. t = 5s

f) The total kinetic energy of the system decreases as a result of the collision. Is the principle of conservation of energy violated? Explain.