# Homework Help: Acceleration and time of blocks with friction acting

1. Mar 7, 2005

### cde42003

Can anyone help me with this problem. I know that I need to find the total total forces for both blocks and combine them to solve for the acceleration and then use the acceleration to find the time. The problem is that I can't seem to get the correct value for the final answer. Thanks in advance

1.The lower block in the figure is pulled on by a rope with a tension force of 20 N. The coefficient of kinetic friction between the lower block and the surface is 0.30. The coefficient of kinetic friction between the lower block and the upper block is also 0.30.

What is the acceleration of the 2.0 kg block?

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Last edited: Mar 7, 2005
2. Mar 7, 2005

### dextercioby

Okay.Post some of your work/ideas and we'll where and if you went wrong...

Daniel.

3. Mar 7, 2005

### cde42003

I am not sure how to post the work with the correct icons. What I have done is taken the total forces on block(1kg) and block(2kg).

1.Netforce on Block 1= friction(between blocks 1 and 2) - tension= ma
2.Netforce on block 2= 20N-tension-friction(between blocks 1 and 2)-friction(block 2 and surface)

Then I solved the first equation for tension and substituted into the 2nd and solved for the acceleration, but did not get the right answer

4. Mar 7, 2005

### cde42003

Nevermind. I figured out the problem.