Question

A motor with a power of 7.0 × 104 watts lifts a loaded elevator to a height of 20.00 meters for 40 seconds. What is the force exerted by the motor on the elevator?

Answer 1

C) 1.4 × 105 newtons

Step-by-step explanation:

Correct answer on plato/edmentum

Answer 2

`1.4\cdot 10^5 N`

Step-by-step explanation:

First of all, we can find the work done as follows:

`W=Pt`

where P is the power and t is the time taken. In this problem,
`P=7.0\cdot 10^4 W` and
`t=40 s`, so the work done is

`W=Pt=(7.0\cdot 10^4 W)(40 s)=2.8\cdot 10^6 J`

The work done is equal to the force applied F times the displacement d:

`W=Fd`

since we know d=20.0 meters, we can re-arrange the equation to find the force exerted:

`F=(W)/(d)=(2.8\cdot 10^6 J)/(20.0 m)=1.4\cdot 10^5 N`