Three blocks on a frictionless horizontal surface are in contact with each other (Ma-Mb-Mc).?

Question

A Force F is applied to block A (mass Ma)

1.Determine the acceleration of the system (in terms of Ma,Mb, & Mc)
2. Determine the net force on each block
3. Determine the force of contact that each block exerts on its neighbor.
4. If mA=mB=mC=12.0kg and F=96.0N, give numerical answers.
5. Do the answers make sense intuitively?

Answer 1

1.
a = F/(Ma +Mb + Mc)

2.
Fa = F - a(Mb + Mc)
Fb = F - a(Ma + Mc)
Fc = F - a(Mb + Mc)

3.
F(a-b) = F - aMa
F(b-c) = F - a(Ma + Mb)

4.
If you can't fire up a calculator and figure this one out, it won't make any difference. You'll be taking the class over again ☺

5.
They'd better. If they don't, you need to re-think your intuition ☺


Doug