Find the ratio of their speeds immediately afterward.

Question

Two persons on ice skates stand face to face and then push each other away (see figure below). Their masses are 70 and 90 kg.

Find the ratio of their speeds immediately afterward.

Answer 1

You can use conservation of momentum. m1v1 = m2v2, so m1/m2 = v2/v1 and so (speed of the 90 kg person) / (speed of 70 kg person) = 70/90 = 7/9