1. The problem statement, all variables and given/known data Two masses A and B, and of mass 1.6kg and 2.4kg respectively are connected by a light string which passes over a frictionless pulley. Calculate the acceleration of the 1.6kg mass. 2. Relevant equations 3. The attempt at a solution To get started I must know whether the two masses both have the same acceleration. Is that true? I know the tension of the system is the same. Assuming it's true I get a simultaneous equation that looks like 16-T=1.6a 24-T=2.4a which works out for a=10m/s^2 and T=0 which is a bit fishy. But if a is different for each mass than there are 3 variables but only two equations.