In this tutorial I look at two particles of different masses attached by an inextensible string passing over a smooth pulley where the strings hang verticaly.
I tell what assumptions are made and the effect they have.
You will be shown you how to set up the general equations of motion that you should then be able to apply in similar problems.
After the tutorial is an example that I would encourage you to try.
Two particles A and B of masses 3kg and 5kg respectively are attached by a light inextensible string passing over a smooth pulley. Calculate the tension in the string and the acceleration of the particles.