Joel and bobby each move an identical box from the ground to a shelf that is 1.2m from the ground. joel moves his box in half the time it take s bobby to move his box. what is the ratio of joel's power output to bobbys power output

A1500 w electric heater is plugged into the outlet of a 120 v circuit that has a 20 a circuit breaker. you plug an electric hair dryer into the same outlet. the hair dryer has power settings of 600 w, 900 w , 1200 w, and 1500 w. you start with the hair dryer on the 600 w setting and increase the power setting until the circuit breaker trips. under what setting does the circuit breaker trip.