A boy throws a ball so that it may just clear a wall 3.6 m high. The boy is at a distance of 4.8 m from the wall. The ball was found to hit the ground at a distance of 3.6 m on the other side of the wall. Find the least velocity with which the ball can be thrown. A 3.6 m B X 4.8 m 3.6 m Fig. 12.8 The acceleration is defined by a = -kx2. The particle starts with no initial velocity at x = 0.8 m and its velocity becomes 6 m/s when x = 0.5 m. Determine the value of k. Also determine the velocity of the particle when x = 0.25 m. A jet of water is discharged at A with a velocity of 20 m/s to strike a moving plate B, as shown in Fig. 12.E23. If the plate is moving downward with velocity of 1 m/s. determine the relative velocity of water w.r.t. the plate just before it strikes. A 20 m/s 1 m/s B 6 m Fig. 12.E23 The acceleration of the train, starting from rest, at any instant is given by the expression a = 8 [241] m/s, where v is the velocity of the train in m/sec. Find the velocity of the train + when its displacement is 20 m and its displacement when velocity is 64.8 kmph.