2 really tricky ones for me on this homework assignment. I think I got the other one settled (Thanks to help here) -- now I just need to finish this last one.(adsbygoogle = window.adsbygoogle || []).push({});

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

Two blocks sit on this frictionless table, but there is friction between the blocks.

Static = .589

Kinetic = .332

A = 100 kg

B = 10 kg

What minimum force F must be exerted on A in order for B not to fall?

2. Relevant equations

F=m•a

R - the static resistive force ---> fs*F=R

3. The attempt at a solution

Attempt 1:

Since B isn't moving, I'll use the static friction force. I know that the force that A applies on B, times the static force, will be my upward force -- which I need to counter the downward force of gravity.

Since B is 10kg, I need 98 kg of up force.

98/589 = 166.4 N

So

Force to move block A = 980 N

Force to move block B = 98 N

980+98+166.4=1244 N

The only problem is I am given a range for the answer, and I need to be between 1700 and 2200, so I know that answer is wrong.

Once I find the force, then I'm supposed to find the overall acceleration...I think that should be easy, once I know the force.

**Physics Forums | Science Articles, Homework Help, Discussion**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Two blocks on frictionless table, friction between blocks (Blocks side by side)

**Physics Forums | Science Articles, Homework Help, Discussion**