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: How does one do this question?

  1. Nov 20, 2012 #1
    Figure attached below. You have a big block of mass M and a small block of mass m. When m=3kg, the acceleration of the large block is 0.6ms-2. When m=4kg, the acceleration of the large block is 1.6ms-2. The dynamic friction coefficient between the large block and the surface it slides on is μ. There is no friction between any other surface. Questions:

    a) Express the relationship between the movement of block m and block M
    b) Derive expressions for the motion of block m and block M.
    c) Determine the mass of block M and the dynamic friction coefficient, μ, between it and the surface it slides on.

    Last edited: Nov 20, 2012
  2. jcsd
  3. Nov 20, 2012 #2


    User Avatar
    Science Advisor

    Nice problem. So what have you got so far? How does the motion of mass m relate to the motion of mass M?
  4. Nov 20, 2012 #3
    I know that [itex] x_m = 2 x_M [/itex], so that the small block moves two times as much as the big block. My problem is decomposing the forces.
  5. Nov 20, 2012 #4


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    Draw free body diagrams. Start with the mass m. What forces are acting on m?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook