does mass affect acceleration of a body in a frictionless inclined plane?
Look at the diagram. Since we are on a frictionless incline, the only force acting on the blue object along the incline is the component of the force of gravity ($\displaystyle F_g$) parallel to it, i.e. $\displaystyle mg\sin \theta$).
So, the net force acting on the object along the incline is given by: $\displaystyle F_{\text{net}} = mg \sin \theta$
But what do we know about $\displaystyle F_{\text{net}}$ ? Newton's second law!
Do you have any experience solving these sorts of problems?
You can do the experiments at this website:
CalcTool: Object on a slope calculator
Give M different values and see what happens to the acceleration.