# Tension, kinetic friction, and two blocks

1. Oct 24, 2004

### FIONEX

Hey guys,

I have a physics problem that I tried to solve but I am not positive of the answer I got. Can someone guide me through the steps of solving it.

Problem: Two blocks connected by a rope are dragged by a horizontal force (68 N
). The first block is 18Kg, the second block is 12Kg, and the coefficient of kinetic friction is 0.100. What is the tention of the rope between the two blocks. What is the acceleration of the system.

For the acceleration, I got 1.3m/s^2, and the tention turned out to be 95 N. It's the tention that I'm really iffy about. But that could be due to a miscalculation of my acceleration.​

2. Oct 24, 2004

### Pyrrhus

Equations for each block

$$T_{applied} - T_{block} - \mu m_{2}g = m_{2}a$$

$$T_{block} - \mu m_{1}g = m_{1}a$$

Solving:

$$\frac{T_{applied} - \mu m_{2}g - \mu m_{1}g}{m_{1}+m_{2}} = a$$

Then

$$T_{block} - \mu m_{1}g = m_{1}a$$

Plugging
$$T_{block} - \mu m_{1}g = m_{1}(\frac{T_{applied} - \mu m_{2}g - \mu m_{1}g}{m_{1}+m_{2}})$$