Question

A blue ball is thrown upward with an initial speed of 23.9 m/s, from a height of 0.8 meters above the ground. 2.9 seconds after the blue ball is thrown, a red ball is thrown down with an initial speed of 12.9 m/s from a height of 32.1 meters above the ground. the force of gravity due to the earth results in the balls each having a constant downward acceleration of 9.81 m/s2. 1) what is the speed of the blue ball when it reaches its maximum height?

Answer 1

At the exact instant the blue ball reaches maximum height, it is stationary for that millisecond in time before it begins to fall, therefore its speed is zero. (The other factors listed have no effect on the speed at the moment of maximum height.)