Answer all questions in the spaces provided 1. (a) What is meant by inertia (in linear motion)? [2] (b) What is meant by moment of inertia (in rotational motion). [2] (c) In the space below, calculate the moment of inertia of a 12 kg disc of radius 4 m. [2] (For a disc, I = 1/2 MR.) (Show your steps in the calculation, but you need not go into detail such as 'To Find', 'Given') 2. (a) Define frequency of rotation, f [2] (b) Define angular frequency of rotation c [2] (c) The disc in question 1 makes 48 r.p.m. In the space below, calculate (i) its frequency, fin Hz (ii) its angular frequency, @ (iii) its angular momentum, L. [3]Conservation of angular momentum: (angular momentum L = I co) In a system of two colliding objects R and D, the total angular momentum before collision = the total angular momentum of the system after collision (providing there are no external torques like frictional torques acting in the system). This is a statement of the of Conservation of Angular Momentum. In equation form: IR OR + ID WOD = IR OR' + ID (D' IR 2xfr + ID 2xfo (IR + ID) 2afRD ' (since @) = 2xf) Therefore, IR fr + ID fo = (IR + ID) fRD ' ...... (1) (angular momentum before collision) (angular momentum after collision) 3. A stationary 2 kg ring of radius 0.20 m is dropped from rest on to a freely rotating 10 kg disc of radius 0.20 m rotating at 16 Hz (see picture below). Stationary ring Spinning disc (a) Draw labelling lines to the disc and the ring. [2] ( b) Calculate the moment of inertia of the ring (Iring = MR?). [2] (c) Calculate the moment of inertia of the disc (Idisc = = MR?). [2] (d) State the initial rotational frequency, fr , of the ring in Hz. [1] (e) State the initial rotational frequency, fo, of the spinning disc in Hz. [1] (f ) Assuming angular momentum is conserved, use equation (1) to determine the final rotational frequency, fRD' , of the ring and disc combination. [2]