24 7. [In this question, i and j are perpendicular unit vectors in a horizontal plane.] (8i + 2j) m s−1 v m s−1 A B Figure 3 Figure 3 represents the plan view of part of a smooth horizontal floor, where AB is a fixed smooth vertical wall. The direction of AB → is in the direction of the vector (i + j) A small ball of mass 0.25 kg is moving on the floor when it strikes the wall AB. Immediately before its impact with the wall AB, the velocity of the ball is (8i + 2j) m s−1 Immediately after its impact with the wall AB, the velocity of the ball is v m s−1 The coefficient of restitution between the ball and the wall is 1 3 By modelling the ball as a particle, (a) show that v = 4i + 6j (6) (b) Find the magnitude of the impulse received by the ball in the impact. (3) _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________