When a ballplayer throws a ball straight up, by how much does the speed of the ball decrease each second while ascending? In the absence of air resistance, by how much does it increase each second while descending? How much time is required for rising compared to falling?
Solution 29E Part 1 Now when the ball is moving upwards, the acceleration is in the opposite direction. So the speed will 2 decrease. Now the acceleration due to gravity is 9.8 m/s . So in each second the speed of the ball will decrease by 9.8 m/s. Part 2 While descending, the direction of the velocity and the acceleration are same. Hence the velocity of the ball will increase. Since the acceleration of the ball is same, that is, 9.8 m/s , the velocity of the ball will increase by 9.8 m/s in each second. Part 3 Since the ball is travelling with influence of the same gravitational force both while going up and coming down. So in the two cases, the distance is same, acceleration is same, and the velocities at the top and bottom are also same. Hence the time taken to travel this distance will also be same. So the time required for rising and falling are equal.
