Question

An ideal string passes over a fixed pulley and carries masses M1 = 12kg and M2 = 8kg tied at its end. Calculate the acceleration of masses and tension in the string when released (g=10m/s2)

I know the answers are
a = 2 m/s^2
T = 96 N

But I don't know how to get there

Answer 1

the net accelerating force is the difference in the weights (gravitational force) of the two masses

a = f / m = (120 N - 80 N) / 20 kg

find tension by looking at the smaller mass
... net force required for acceleration

T - W = 8 kg * 2 m/s^2 ... T - 80 N = 16 N

Answer 2

Thanks, Scott!!