1. The problem statement, all variables and given/known data A block of mass M has a string of mass m attached to it. A force F is applied to the string and it pulls the block up a frictionless plane that is inclined at an angle theta. Find the force that the string exerts on the block 2. Relevant equations F=ma 3. The attempt at a solution Force of the string on the block = Force of the block on the string = N Force applied to string = F acceleration of block = acceleration of string = a My first equation was the net-force equation for the string: ma = -mg*sin(theta) - N + F My second equation was the net-force equation for the block: Ma = -Mg*sin(theta) + N solving for the acceleration in the top equation and plugging it into the second equation gives the following (after a small amount of algebra) N = (F/m)*(1+M/m)^-1 Which is not the answer I am supposed to be getting. I am guessing the problem is with my net-force equations but I can't located a specific problem. Anyone want to explain what I'm doing wrong here?