Question

I tossed a ball straight up into the air and timed how long it took to return to the height I tossed it from. It took 4.2s. How fast did I throw the ball into the air?

Answer 1

Explanation:

$v = u + at \\ 0 = u + ( - 10 { ms}^{ - 2}) \times 4.2s \\ u = 42 {ms}^{ - 1}$