- #1
Dave27
Homework Statement
Suppose there are 2 boxes over a horizontal surface. One has mass M and the other one has mass m. The one with mass m is over M as shown in the picture and a horizontal force is applied to pull M. There is no friction between M and the surface, but there is friction between m and M. The question is how large the coefficient of friction needs to be to occur no slip at all between m and M if the force applied is 100N. Also, let's say M = 5kg, m = 2kg.
Homework Equations
Some free body diagrams:
For m
Acceleration of the system:
F = (M+m)a
a = F / (M+m)
For m:
The force of friction for it not to slip should be at least equal to F so there's no acceleration.
Ff = u * Fn
Ff = umg
Ff = Fm
umg = ma
a here should be the acceleration of the system
The Attempt at a Solution
[/B]
Plugin in numbers:
u (2kg)(9.8m/s^2) = (2kg)(100N/(5kg+2kg))
u 19.6N = 2kg ( 14.3 m/s^2 )
u 19.6N = 28.6N
u = 1.46 ~