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Mechanics "Proof" Exercises

Question 1

A body, of mass m, is moving in a circular path of radius r. The centripetal force acting on it is Fc. Show that the rotational frequency of the motion is given by

Question 2

A piece of metal is given an initial kinetic energy, K, near the bottom of a plane inclined at q degrees to the horizontal. The coefficient of dynamic friction between the metal and the inclined plane is µ.

The centre of gravity of the piece of metal moves through a vertical distance, h, before coming to rest. Using the principle of conservation of energy, show that the relation between h and K is

Question 3

An apple falls from a height, h, on to the head of a typical I.B. student. Show that the change in I.Q. experienced by the student, as a result of the collision, is given, approximately, by

© David Hoult 2008