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: F=ma problem, I feel retarded because I can't get it

  1. Feb 3, 2009 #1
    Seriously I feel so stupid because I can't get the answer to the second part of the problem, what am I doing wrong?

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

    2 parts to the problem:

    An empty truck whose mass is 1500 kg has a maximum acceleration of 1.4 m/s^2 . What is the maximum force that accelerates the truck? ______N

    What is the maximum acceleration when it is carrying a 500 kg load? (hint: same force, but new total mass) ______m/s^2

    2. Relevant equations


    3. The attempt at a solution

    This is for a web based quiz and I got the first part right, it's obviously 2100 N, so then I figured: ok, so to find the acceleration using the same force just solve for a, therefore it should be 2100 N/500 kg, which gives me an answer of 4.2 m/s^2. It's telling me the 2100 N is correct, but not the 4.2 m/s^2 ... what am I doing wrong or not taking into consideration? It's so easy I'm just missing it...
  2. jcsd
  3. Feb 4, 2009 #2
    Force = TOTALmass * acceleration

    What is the TOTALmass
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook