Suppose that the gravitational acceleration on a certain planet is only 3.1 m/s2. A space explorer standing on this planet throws a ball straight upward with an initial velocity of 35 m/s

a) What is the velocity of the ball 4 seconds after it is thrown?
m/s

(b) How much time elapses before the ball reaches the high point in its flight?
s

2 answers

(a)
v = 35 - 3.1t
solve for v when t=4

(b)
solve for t when v=0
i need help