c. angle at which work 4. Two machines (e.g, elevators might do identical jobs (e.g., lift 10 passengers three floors) and yet the machines might have different power outputs. Explain how this can be so.

The power output of a machine is determined by the rate at which it does work. Work is defined as the force applied to an object times the distance the object is moved (Work = Force x Distance). Power is the rate at which work is done, or the amount of work done per unit of time (Power = Work/Time).<br /><br />Two machines can do the same job (e.g., lift 10 passengers three floors) but have different power outputs if they do the work at different rates. For example, if Machine A lifts the 10 passengers three floors in 10 seconds, its power output would be (Work = Force x Distance = 10 passengers x 3 floors = 30 passenger-floors) and Power = Work/Time = 30 passenger-floors/10 seconds = 3 passenger-floors/second. If Machine B does the same job in 5 seconds, its power output would be Power = Work/Time = 30 passenger-floors/5 seconds = 6 passenger-floors/second. Thus, Machine B has a higher power output than Machine A, even though they do the same job.<br /><br />In summary, two machines can do the same job but have different power outputs if they do the work at different rates.