Homework Help: Applying Newton's Laws

1. Oct 5, 2008

DKphysics

A 25,000-kg rocket blasts off vertically from the earth's surface with a constant acceleration. During the motion considered in the problem, assume that g remains constant. Inside the rocket, a 15.0-N instrument hangs from a wire that can support a maximum tension of 35.0 N.

a) Find the minimum time for this rocket to reach the sound barrier (330 m/s) without breaking the inside wire and the maximum vertical thrust of the rocket engines under these conditions.

b) How far is the rocket above the earth's surface when it breaks the sound barrier?

I have no idea where to start with this problem. The answers in the back of the book are:
(a) 25.3 seconds; 5.72 x 10^5 N/s
(b) 4170 m

2. Oct 5, 2008

hage567

Start by drawing a free body diagram of the weight hanging inside the rocket.

3. Oct 5, 2008

Okay

4. Oct 5, 2008

hage567

So once you have that, what do you think you can do next?

5. Oct 13, 2011

IDKFysics

A 2.49e4 kg rocket blasts off vertically from the earth's surface with a constant acceleration. During the motion considered in the problem, assume that g remains constant. Inside the rocket, a 12.4 N instrument hangs from a wire that can support a maximum tension of 36.0 N.

a) Find the minimum time for this rocket to reach the sound barrier (330 m/s) without breaking the inside wire and the maximum vertical thrust of the rocket engines under these conditions.

b) How far is the rocket above the earth's surface when it breaks the sound barrier?

I have no idea what to do.

6. Oct 14, 2011

SteamKing

Staff Emeritus
Go to Post #2. Follow steps there.

(It's better not to add new problems to old posts.)

7. Oct 14, 2011

Matterwave

Are you mocking the other guy by making a name similar to his? I find this either very coincidental, or pretty hilarious...