# Question about newton's second law

1. Nov 11, 2008

### Elclon

A 4.0 kg block is put on top of a 6.0 kg block. In order to cause the top block to slip on the bottom one when the latter is held fixed, a horizontal force of 12N must be applied to the top block to overcome the maximum static friction. The coefficient of kinetic friction for all contact surfaces is 0.25.
(a) Find the coefficient of static friction between the two blocks.
(b) Find the maximum horizontal force F that can be applied to the lower block so the blocks will move together. (Hint: In this situation, the two blocks still have the same acceleration, while the block on top receives maximum available static friction.) Please draw a free body diagram for each block.
(c) If the horizontal force on the lower block is twice the maximum value calculated in (b) above, draw a free body diagram for each block, and find the accelerations of each block.

2. Nov 11, 2008

### LowlyPion

Welcome to PF.

How would you think to approach the problem?

3. Nov 11, 2008

### Elclon

I don't even have a clue when dealing with one object is being put on top of another object. Is there anyone who can help me to solve that?

4. Nov 11, 2008