PLEASE HELP !! A jet plane traveling horizontally at 1200km/h relative to the ground fires a rocket forward at 1100km/h relative to itself. what is the velocity of the rocket relative to the ground​

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.