Undergrad How to Calculate Fall Duration with Variable Force?

[Dylanden]

Hello.

How can one calculate the duration of fall of an astronaut "lost" to 20 m of his shuttle? We can assume that they are stopped at the beginning of the fall.
I do not see how.

Dylan

 

[phinds]

Hello.

How can one calculate the duration of fall of an astronaut "lost" to 20 m of his shuttle? We can assume that they are stopped at the beginning of the fall.
I do not see how.

Dylan

Your question is completely unclear. I cannot figure out WHAT you are trying to ask.

 

[Dylanden]

Hello.

Thank you for your answer

I just want to make an exercice for my lesson.
Imagine we have a shuttle in the space and an astronaut at about 20 m from its.
How many time does it take to the astronaut to fall on his shuttle.
There is only the gravitational force in action.
Sorry for my poor english.

Dylan

 

[phinds]

Hello.

Thank you for your answer

I just want to make an exercice for my lesson.
Imagine we have a shuttle in the space and an astronaut at about 20 m from its.
How many time does it take to the astronaut to fall on his shuttle.
There is only the gravitational force in action.
Sorry for my poor english.

Dylan

(1) Uh ... do you think it matters how much mass is involved?
(2) You say "about 20m from it" but that's probably 20m from the SKIN. How far from the center of mass?

You really don't seem to have thought through what you need to know to make this a meaningful question.

 

[Dylanden]

Hello.

It's only for my mechanics class.
To illustrate the gravitational forces.
Let's say that the astronaut weighs 100 kg.
And the shuttle 10000 kg. For simplicity.
And that the distance of 20 m is measured between the centers of mass. And that the astronaut must arrive 5 m from the center of mass of the shuttle to be able to seize it with his hand.
My students are francophones. They asked the question on different physics sites in French. I have not read all the answers yet. But it's very confusing. I hope you can help me.
I tried to integrate Newton's laws. To find the duration. I can not do it.

Good day there.

Dylan

 

[DrClaude]

You'll have to repost in the Introductory Physics Homework and fill the homework template, showing an attempt at a solution.

Thread closed.

Edit: @gmax137 suggest you check out the following threads:
https://www.physicsforums.com/threads/dealing-with-variable-force.306442/

https://www.physicsforums.com/threads/non-constant-accelleration-equation-s.635188/

https://www.physicsforums.com/threads/radial-movement-in-a-gravitational-field.927164/