problem 3: from a rest, a child swings down and picks up a box. the boy has a mass of 40 kg, and the box has a mass of 10 kg. (1) what is the speed of the child moving just before picking up the box? (2) what is speed of the child immediately after picking up the box (before swinging up again)? (3) how much energy was transformed into thermal energy during the pick up? (4) how high above the ground will the boy swing to the other side? (5) how much tension must have been in the rope right before the boy picked up the box? how does that value change after grabbing the box?