# B Math problem finding the top velocity of an object with a certain force applied in a vacuum

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1. Nov 4, 2017

### matliolec

ok i have a simple enough scenario that i need a hand with solving. first off just to say, i dont know how to do the math for it so maybe someone here could help me out.

basically has to do with finding the top velocity of an object with a certain force applied. all in a vacuum and without any form of resistance of course.

so lets say object A (a cubic foot rock, at a 100lbs in weight on earth) is motionless in space. and object B applies a 100lbs of force on the rock for a tenth of a second every 5 seconds..

oh and as the mass of the rock increase with speed the time between applied force will also decrease.

how long will it take to reach its maximum velocity and how fast will object A and the rock (object B) be going with it pushing on the rock at all time.

Last edited by a moderator: Nov 4, 2017
2. Nov 4, 2017

### Staff: Mentor

Welcome to the PF.
No can do. The speed of light "c" is the upper speed limit -- extremely energetic particles can get very close to c, but never reach it.

Last edited: Nov 4, 2017
3. Nov 4, 2017

### matliolec

be open minded please. its just a way to say that object A is ONLY limited by object B. and how much.

4. Nov 4, 2017

### Staff: Mentor

No can do. We don't discuss fantasy in the technical PF forums.

5. Nov 4, 2017

### matliolec

fine then. edited. one moment.

6. Nov 4, 2017

### Ibix

If Newtonian physics were true its speed relative to its starting frame would tend to infinity. It's not true, though, and in relativity the answer is that its speed will tend towards, but never reach, c relative to its starting frame.

In practice the speed would be limited by the fuel supply of whatever was doing the accelerating. When it runs out you can't accelerate any more.

7. Nov 4, 2017

### matliolec

huh? who said anything about fuel. did u read it? no fuel, constant applied force.

8. Nov 4, 2017