At the local playground, a 21-kg child sits on the right end of a horizontal teeter-totter, 1.8 m from the pivot point. On the left side of the pivot an adult pushes straight down on the teeter-totter with a force of 151 N. Required:
a. In which direction does the teeter-totter rotate if the adult applies the force at a distance of 3.0 m from the pivot?
b. In which direction does the teeter-totter rotate if the adult applies the force at a distance of 2.5 m from the pivot?
c. In which direction does the teeter-totter rotate if the adult applies the force at a distance of 2.0 m from the pivot?