The suspended 2.3 kg mass on the right is moving up, the 2.4 kg mass slides down the ramp, and the suspended 7.2 kg mass on the left is moving down. There is friction between the block and the ramp. The acceleration of gravity is 9.8 m/s2. The pulleys are massless and frictionless.
What is the tension in the cord connected to the 7.2 kg block? Answer in units of N.
Here is a photo:
The Attempt at a Solution
I split it up into gravity parallel and gravity perpendicular and did the following to get those values:
sin23 * 23.52 = 9.19 N (parallel)
cos23 * 23.52 = 21.65 N (perpendicular)
Since the perpendicular force is equal to the normal force, the value of the normal force is also 21.65 N. Then I plugged the following to find the friction force:
0.12 = Ff/21.65
Ff = 2.598 N
Then, I found the gravitational forces on the blocks hanging on the two sides.
7.2 kg * 9.8 m/s^2 = 70.56 N
2.3 kg * 9.8 m/s^2 = 22.54 N
This is the part I'm currently stuck on. Do I add up all the forces on the 2.4 kg block? Or do I have to use a summation to find the tension in the 7.2kg string?