KE+PE when a rocket's speed is less than escape velocity?

[GrimReaper]

Hey people, I just want to ask that what will happen to the total mechanical force of the rocket if its speed is less than escape velocity?
a. KE+PE=0
b. KE+PE>0
c. KE+PE<0
d. Depends upon initial speed of the rocket
Pick one. And Why??

 

[Gabriele Pinna]

I guess C because at infinity we will have PE=0 and KE> 0 or equal to zero. As the rocket has not the tendency to move to infinity we conclude that
PE+KE <0

 

[haruspex]

I guess C because at infinity we will have PE=0 and KE> 0 or equal to zero. As the rocket has not the tendency to move to infinity we conclude that
PE+KE <0

I appreciate that it was a bit tricky with this one, but the rule on homework forums is to give hints and point out errors, not provide complete solutions.
Correspondingly, @GrimReaper should have used the homework template and shown some attempt before meriting any help.

 

[GrimReaper]

I appreciate that it was a bit tricky with this one, but the rule on homework forums is to give hints and point out errors, not provide complete solutions.
Correspondingly, @GrimReaper should have used the homework template and shown some attempt before meriting any help.

I appreciate that it was a bit tricky with this one, but the rule on homework forums is to give hints and point out errors, not provide complete solutions.
Correspondingly, @GrimReaper should have used the homework template and shown some attempt before meriting any help.

I'm sorry if it was a mistake. And I'm totally new to this so I actually don't know how to use this. Thank you for the directions @haruspex.

 

[haruspex]

I'm sorry if it was a mistake. And I'm totally new to this so I actually don't know how to use this. Thank you for the directions @haruspex.

Please read https://www.physicsforums.com/threads/guidelines-for-students-and-helpers.686781/

 

[GrimReaper]

Please read https://www.physicsforums.com/threads/guidelines-for-students-and-helpers.686781/

Thank you very much.

 

[mjc123]

Why is there no answer to this question? (Apart from the obvious fact that the question asks about force and gives answers in energy...)

 

[haruspex]

Why is there no answer to this question? (Apart from the obvious fact that the question asks about force and gives answers in energy...)

The reference to force in the question statement is clearly an error. It should have said energy.
The answer is given in post #2.

 

[GrimReaper]

The reference to force in the question statement is clearly an error. It should have said energy.
The answer is given in post #2.

oh sorry, actually its energy. I mistakenly typed force.