Q1. A 5 m long board is balanced on a point pivot to make a seesaw. A 30 kg child sits on one end of the seesaw, 3m from the pivot. A 47 kg child sits on the opposite end.

a) If the board is equilibrium with both kids off the ground, what is the board's mass?

b) What force is necessary at the pivot to support the seesaw?

Q2. Sisyphus was a character in Greek mythology that was doomed in Hades to push a boulder to the top of a steep mountain. When he reached the top, the boulder would slide back down the mountain and he would have to start all over again. Assume that Sisyphus slides the boulder up the mountain without being able to roll it, although in most versions of the myth, he rolled it.

If the coefficient of kinetic friction between the boulder and the mountainside is 0.4, the mass of the boulder is 20.0kg, and the slope of the mountain is a constant 30.0°, what is the force that Sisyphus should exert on the boulder to move it up the mountain at a constant velocity?