A green ball is thrown vertically downward to the ground with an initial speed of 5m/s, at time t = 0, from a vertical height of 100m above the ground. 2 second later, a red ball is thrown vertically upward from the ground with an initial speed of 15m/s
a) find the height above the ground where these balls pass each other, if possible, and hence
b) Determine the magnitude and direction of velocity of the red ball when the balls pass each other.