What is the top velocity of an object with a certain force applied in a vacuum?

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The discussion revolves around calculating the maximum velocity of a 100-pound rock in a vacuum when a constant force of 100 pounds is applied intermittently. Participants emphasize that, according to the principles of relativity, no object can exceed the speed of light, and thus the rock's speed will asymptotically approach but never reach this limit. The conversation also touches on the implications of Newtonian physics versus relativistic physics, highlighting that real-world factors like fuel supply can affect acceleration. Ultimately, the thread was closed for moderation due to the inclusion of fantastical elements and the need for adherence to scientific principles. The focus remains on understanding the physics behind force and velocity in a vacuum.
matliolec
ok i have a simple enough scenario that i need a hand with solving. first off just to say, i don't 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 let's 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.
 
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matliolec said:
ok i have a simple enough scenario that i need a hand with solving. first off just to say, i don't 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 let's say object A (a cubic foot rock, at a 100lbs in weight on earth) is motionless in space. and object B (superman.. but this one can go infinitly fast.. but rather weak) 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.

he can't apply more then a 100lbs of force.. how long with it take to reach its maximum velocity and how fast will Mr superman and the rock be going with him push on the rock at all time.

Welcome to the PF. :smile:
matliolec said:
superman.. but this one can go infinitly fast..
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.
 
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be open minded please. its just a way to say that object A is ONLY limited by object B. and how much.
 
matliolec said:
be open minded please.
No can do. We don't discuss fantasy in the technical PF forums.
 
fine then. edited. one moment.
 
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.
 
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Ibix said:
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.
huh? who said anything about fuel. did u read it? no fuel, constant applied force.
 
Thread closed for Moderation...
 
matliolec said:
huh? who said anything about fuel. did u read it? no fuel, constant applied force.
As I mentioned, we do not discuss fantasy in the technical forums. And there are limitations for what can be discussed in the SciFi section of the PF as well. @Ibix was trying to help you understand the simple Special Relativity considerations behind your question.

This thread is not appropriate for the PF and is closed.
 

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