Question

Hi I need help
three objects are connected by massless wires over a massless frictionless pulley as shown in the figure. The tension in the wire connecting the 10kg and 15kg objects is measured to be 133N. What is the tension in wire A? See link for diagram
http://s452.photobucket.com/user/ILoveMaths07/media/54.jpg.html

Answer 1

First of all draw the FBD (i.e. free body diagram) for 15 kg and 10 kg block.

Try following this sequence:

(1) Draw FBD for 10.00 kg block. You would be able to get the acceleration of the block.

(2) Draw FBD for 15 kg block. From step 1 you would have obtained acceleration. This acceleration would be the same for 15 kg block. Now, you have net force (use newton's second law), try obtaining the tension for the wire above 15 kg block.

(3) This tension would be the same in wire A as the wire and pulley are frictionless and massless.

If you have some doubt, feel free to ask.

Hope this helps.

Answer 2

I took these steps
a = T - mg/m = 133- 10(9.8) / 10 = 3.5m/s^2
T1 = ma + mg + T2 = 15kg * 3.5m/s^2 + 15*9.8m/s^2 + 133N = 332.5 N

is 332.5N the tension on wire A?

Answer 3

Great work. I think you have got it rigjt

Answer 4

*right

Answer 5

@jeand199 , your answer is right, I have verified it again.