Calculate the minimum power output of an electric motor that lifts a 1.30 × 10^4-newton elevator car
vertically upward at a constant speed of 1.50 meters per second. [Show all work, including
the equation and substitution with units.]
As the load is lifted, its gravitational potential energy increases by
(1.3 x 10⁴ N) x (1.5 m) = 19,500 joules
every second. THAT's the energy that the motor must provide.
19,500 joules/second = 19,500 watts .
That's the minimum. If there are frictional losses in the works, gears, cables, or guts of the elevator, then the motor must provide the extra energy required to overcome those too .
