# 3 blocks with friction

1. Feb 11, 2008

### BeatTheRuckus

1. The problem statement, all variables and given/known data
There are three blocks on a table. They are connected by a massless cord and pulled to the right. From rigt to left, it follows: T3, block 3, T2, block 2, T1, block 1
m1: 2.5kg
m2: 9.5kg
m3: 1.5kg
mu kinetic: .051
The pulling force is equal to T_3 = 98.0 N. What is the tension T_2?
2. Relevant equations
I think my equations may be incorrect, but here goes
F$$_{}fr$$=F$$_{}N$$ + $$\mu_{}k$$
F$$_{}pull$$=F$$_{}fr$$ + ma

3. The attempt at a solution

I solved for accel. and then plugged it into the equation for tension and I got a value of 81.11 N, but that is not correct.

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

2. Relevant equations

3. The attempt at a solution

2. Feb 11, 2008

### PhanthomJay

The friction force is not correct. For objects in motion, it's $$F_{friction} = \mu_k(N)$$, where N is the normal force between the block and table. You're going to have to calculate it for each block, then use Newton 2 and 'free body diagrams'. Are you familiar with them?