An astronaut plays paddle ball in orbit. The ball is hit with a speed of 5.21 m/s in the positive direction and has an average negative acceleration of 4.5 m/s^2. How far does the ball travel before it stops and begins to return toward the paddle? How long is it moving in the positive direction?
Let's find the time the ball travel before it stops. We can do it in a such way:
T = 5.21[m/s]/4.5[m/s²] ≈ 1.158 seconds.
That time the ball travels
D = 5.21[m/s]*1.158[s] - 4.5[m/s²]*(1.158[s])²/2 ≈ 3 metres.
So, the ball moves about 1.158 seconds in the positive direction and the travelled distance is about 3 metres.