5. A 70 kg woman and her 35 kg son are standing at rest on an ice rink, as shown. They push against each other for a time of 0.60 s, causing them to glide apart. The speed of the woman immediately after they separate is 0.55 m/s. Assume that during the push, friction is negligible compared with the forces the people exert on each other. (a) Calculate the initial speed of the son after the push.