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 inclined at angle θ to the horizontal. Find the force the string exerts on the block. 2. Relevant equations F = ma 3. The attempt at a solution I have uploaded a picture of the free body diagram. My first problem is, what is the force that is keeping the string up? The mass M has the normal force from the inclined plane, and intuitively I know it is the tension in the string that keeps it from moving downwards due to the force mg. So I first started with finding the forces acting on the string. Fx= F - mgsinθ - Mgsinθ = ma Fy= -mgcosθ + ?? = 0 Now the block: Fx= Fstring - Mgsinθ = Ma Fy= N - Mgcos = 0 I assumed the acceleration for both is the same. So I used the force in the x direction of the string to solve for a. a = (F/m) - gsinθ - (Mg/m)sinθ Now we use the force in the x direction for the block. Fstring - Mgsinθ = M((F/m) - gsinθ - (Mg/m)sinθ) = (MF/m) - Mgsinθ - (M2g/m)sinθ Then we have Fstring = (MF/m) - (M2g/m)sinθ. What I would like to know is, am I missing something? This problem was assigned in my upper division Classical Mechanics class (we're using Analytical Mechanics by Fowles and Cassiday). I've never had to do a problem where the string had mass. I went and asked the professor if there was some sort of trick or something, and he said no, just treat the problem like you would in General Physics 1.