Two particles, A and B, of masses mkg and 3kg respectively, are connected by a light inextensible string. Particle B is on a fixed plane which is at an angle of sin⁻¹ 0.6 to the horizontal ground. The string passes over a fixed smooth pulley at the top of the plane. Particle A hangs vertically below the pulley and is 0.75 m above the ground (see diagram). [Figure 4.1] The system is released from rest. In the subsequent motion B moves up a line of greatest slope of the plane and does not reach the pulley. As B moves up the plane there is a constant resistance to its motion of magnitude 10/3 N. The speed of A immediately before it hits the ground is 2ms⁻¹. Use an energy method to find the value of m.