How does one do this question?

EPFLstudent

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.

jbriggs444

Nice problem. So what have you got so far? How does the motion of mass m relate to the motion of mass M?

EPFLstudent

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.

SteamKing

Draw free body diagrams. Start with the mass m. What forces are acting on m?