posted by Lucy X .
(Apparently, I'm not allowed to post URLs, but this question is better illustrated by a diagram, i39. tinypic. com/ 17e336. jpg)
<--P--[BOX A]<--Q--[BOX B]<--R--[BOX C]
There are three boxes attached together with string and being pulled across a frictionless surface. Box A has a mass of 2 kg, box B has a mass of 4 kg and box C has a mass of 4 kg. The strings are labelled P, Q and R respectively.
The force of tension for string P is 250 N. I have to find the force of tension for strings Q and R.
On a system diagram of the entire system, I already found the acceleration (a = F/m = (250/10) = 25 m/s^2). This acceleration is the same for the whole system, right? But I don't know how to find the forces of tension for strings Q and R.