# Homework Help: Finding Tension of String Connecting Two Blocks on a Flat Surface

1. Oct 4, 2011

### Stormi1018

1. The problem statement, all variables and given/known data
Two blocks mA= 5.0 g and mB= 10.0kg are connected to a string. Both blocks sit on a smooth inclined surface where the angle on the inclined plane is 30.0°. Block A is about block B on the incline. Find the acceleration of the system of two blocks. What is the tension TB in the string.

2. Relevant equations
ƩF=m(a)
Fa= mA(g) sin θ
Fb= mBsinθ

3. The attempt at a solution
I used an archived thread to attempt to solve this problem, I got the tension to be 0.

Mass block A= 5.0kg
Mass block B= 10.0 kg
mg of block A= 49 N
mg of block B= 98 kg

Fa= mg of block A (sin30°) = 24.5 N
Fb= mg of block B (sin 30°)= 49 N
First I found the acceleration of the blocks as a whole using the equation ƩFa=m(acceleration of a) : a = 73.5N/15.0kg, so I found acceleration to be 4.9 m/s^2.

Then I drew separate free body diagrams for each block to solve for the tension.

Block A Tension = T+ƩFA=ma(acceleration)
I found the tension to be zero.
I used the same equation for block B except I subtracted the tension from the force because the tension is acting in a negative x direction.
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Oct 5, 2011

### issacnewton

what do you mean by
"Block A is about block B on the incline". please type the problem in original and with figure if there is any.......is the string attached to a pulley or the wall ?