A force F is applied to a dumbbell for a time interval, t, first as in (i) and then as in (ii). In which case does the dumbbell acquire the greater centre-of-mass speed?

Question

G1 Physics · Accepted Answer

The centre-of-mass impulse is ∫F dt = Ft in both cases. Hence the change in centre-of-mass speed is Δv = Ft/M(total), the same in (i) and (ii). The point of application changes the rotation, not the centre-of-mass impulse. Therefore option C.