# Homework Help: Finding mass of stacked block.

1. Nov 12, 2004

### -Justin-

Alright this problem is giving me a massive headache...I would appreciate any help that you have, I missed this the first time and am trying to figure it out now.

Two blocks are resting on a rough surface, with one on top of the other. A force, Fapplied, with magnitude 25 Newtons, is being applied on Block2 from the left, as shown in the figure below. Friction is acting between the surface and the blocks to keep them from moving. They are not moving, but they are on the verge of sliding. The coefficients of friction between Block 2 and the surface are MUs=0.2 and MUk=0.4 .

Here is a link to a picture of the problem if you have trouble understanding what ive typed.
http://img.photobucket.com/albums/v201/b16eh2/147d0b25.jpg [Broken]

Last edited by a moderator: May 1, 2017
2. Nov 12, 2004

### Pandemonium

Here's some help I hope will assist you in arriving to the answer.

Understand that, horizontally, there are three forces on block 2. Two of them are frictional force, the other is the applied force. Let the mass of block 1 be m. Now, what is the frictional force between the two blocks, and what is the frictional force between block 2 and the surface?