FBD Help, please!

1. The problem statement, all variables and given/known data

First of all, thank you for taking your time to look at this. I cannot seem to figure it out!


I may be completely wrong, but I feel like there isn't any tension... If the ship is slowing down, doesn't that mean that the string isn't fully stretched out...? I'm so confused! :confused:

Thank you.

2. Relevant equations

None? It's a FBD?

3. The attempt at a solution

I'm sure this is extremely hard to see but here are my attempts. I've tried them both in the same direction and everything...


Thanks again for everyone's help!
Last edited:


Science Advisor
Homework Helper
Gold Member
Draw the FBD of the instrument. You do note that the 2 forces acting on it are its weight and the tension force in the hanging wire. Since it is given that the acceleration is slowing down the rocket's (and instrument's) velocity, what direction must the acceleration be in?? Then use Newton 2, noting that the net force must be in the same direction of the acceleration. Note also that tension forces always pull away drom the object on which they act. Crunch out the numbers to get the relative scale of the weight and tension forces. (There will always be some tension in the rope, unless the object is in free fall, in which case the wire goes slack (no tension)).
Yay! Thanks Jay! That helped me out and I got it right!

Thank you!


Science Advisor
Homework Helper
Gold Member
You are welcome. Wecome to PF!

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