# Homework Help: Space shuttle's velocity

1. Oct 27, 2004

### UrbanXrisis

A space shuttle is launched from the earth. It reaches an altitude of 100 meters in 6.1 seconds. At 6.1 seconds, a ball is dropped and hits the ground in 8.5 seconds. What is the speed of the space shuttle when the ball is dropped?

I am really stumped by this one

d=0.5at^2
100=(0.5)a (6.1s)^2
a=5.37m/s^2

Vf=vi+at
v=(5.37m/s^2) * 6.1s
v=32.757m/s?

Last edited: Oct 27, 2004
2. Oct 27, 2004

### Staff: Mentor

keep your eye on the ball

This assumes that the shuttle uniformly accelerates. Instead, analyze the motion of the falling ball, since the ball and shuttle have the same speed when the ball is dropped.

3. Oct 27, 2004

### UrbanXrisis

I've looked at this problem in many different ways already. Trust me, I need more clues. I've tired all posibilities

4. Oct 28, 2004

### Leong

the ball has upward velocity same as the space shuttle the moment it is dropped. the ball falls under the effect of gravity. your assumption about the rocket which moves with constant acceleration is not valid as doc al said. keep your eye on the ball, not the rocket. i got 30 m/s.

Last edited: Oct 28, 2004
5. Oct 28, 2004

### UrbanXrisis

could you explain what you mean by "keep the eye on the ball"?

6. Oct 28, 2004

### UrbanXrisis

The ball goes up then once it is released, it will still go up but with decreasing velocity. Then, it will start to fall and pass the same point it was released with equal velocity as when it was released. It then accelerates downwards and hits the floor...I dont see any equation or way in solving this. I need to know the distance it travled to reach its max point...or some kind of clue

7. Oct 28, 2004

### UrbanXrisis

nevermind, I got it...I thought it would be more complex...