1. A thrower, standing at point P throws a ball at an angle of 30° aiming a basket kept at point O, which is at a height of 18 m from the ground as shown in Fig. 1. The ball passes through point O' which is just 3 m below the point O. Both O and O' are the highest points of the trajectories. Consider the magnitude of gravitational acceleration g = 9.81 m/s². Oʻ Q R Fig. 1 (a) At what velocity the ball should have been thrown to reach point O if the throwing angle remains the same? (b) Calculate the velocity of the ball 0.4 seconds after the throw. (c) When the ball is at point O', calculate its velocity. When the ball is at point O', a man starts to run from point Q (towards point (d) R) to reach the ball, with uniform acceleration. When the ball hits the ground, he was 5 m behind. Calculate his acceleration.

1. A thrower, standing at point P throws a ball at an angle of 30° aiming a basket kept at point O, which is at a height of 18 m from the ground as shown in Fig. 1. The ball passes through point O' which is just 3 m below the point O. Both O and O' are the highest points of the trajectories. Consider the magnitude of gravitational acceleration g = 9.81 m/s². Oʻ Q R Fig. 1 (a) At what velocity the ball should have been thrown to reach point O if the throwing angle remains the same? (b) Calculate the velocity of the ball 0.4 seconds after the throw. (c) When the ball is at point O', calculate its velocity. When the ball is at point O', a man starts to run from point Q (towards point (d) R) to reach the ball, with uniform acceleration. When the ball hits the ground, he was 5 m behind. Calculate his acceleration.