Question 4 (5 marks) A light rectangular piece of card ABCD has the following dimensions: AB = 6 cm and AD = 9 cm. Three objects of masses my-40g, ma- 30g and ma = 20g are placed at the corners A, B and C as shown on Figure 3 below. A B m2 m3 D Figure 3 a) A mass, ma, is placed at corner D. Find the value of m, such that the centre of mass of the whole system lies 2 cm to the right of AD. (3 marks) b ) With the mass me in place at corner D, find the distance of the centre of mass of the whole system from side CD. (2 marks)