1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Basic question on F=ma

  1. Oct 21, 2007 #1
    I know this is rather basic, but some how I confused myself... The question is:

    An astronaut of mass 75 kg performs repair work on the 1700 kg satellite, while floating right next to it. He exerts a force of 180 N on the satellite.
    What is his acceleration as a consequence of this, and what is the acceleration
    of the satellite?

    Ok, I know the force acting on the satellite is 180 N and the force acting on the astronaut is -180 N, because newtons 3rd law (F=-F)

    Now here is my main question. I know to solve I need to Use F=MA for both the astronaut and satellite but, is their mass relevant?

    So is it:
    F/M =A
    -180/75 =A OR -180/75=A
    -2.4 m/(s^2) und =A

    180/1700 =A or 180/0= A
    .105882 m/s^2 =A und=A

    Sorry, for asking such a duh! kind of question but, I am taking AP Physics as an online course and the grading policy is crazy and the teacher and course mat'ls are useless.
    Last edited: Oct 21, 2007
  2. jcsd
  3. Oct 21, 2007 #2
    Yes, their mass is relevant. The astronaut will move away faster than the satellite will. The formulas for the acceleration that you have are correct.
  4. Oct 21, 2007 #3
    Thanks, I just needed someone to make sure I wasn't being stupid.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook