A 65 kg man raises himself from the ground to a tree branch at a height of 5 m above him by holding onto a rope that runs up over a frictionless pulley and down to a hanging 70 kg sandbag. If the man starts from rest, and the sandbag does not hit the ground:
(a) Find the time the man takes to reach the branch.
(b) Find the speed with which the man arrives at the branch.