Question

A ball is thrown straight up from the ground with a speed of 4.0 m/s. (a) how much time elapses between the two moments when it’s velocity has a magnitude of 2.5 m/s?(b) how far is it from the ground at those times? I got an answer of a) 0.15 seconds and b) 0.50 metres. Is this correct?

for a) I used v2 = v1 + at. I assumed that v1 = 4.0 and v2 = 2.5 and that a = -9.8

Answer 1