Question

A 25 kg box is lifted to a height of 6 m. If the lift required 400 watts of power, what distance was the box lifted?

Group of answer choices

2.8 m

4.5 m

4.2 m

3.7 m

Answer 1

Step-by-step explanation:

many greetings to your teacher : the question and answer options are wrong.

let's repeat the basic definitions :

Force = mass × acceleration

for a lift the acceleration is going against Earth's gravity : 9.81m/s²

so, we have

F = 25kg × 9.81m/s² = 245.25 N

Work = force × distance

so, we have

W = 245.25 N × 6 m = 1,471.5 J

Power = work / time

so, we have

400 watts = 1,471.5 J / time

time = 1,471.5 J / 400 watts = 3.67875 ≈ 3.7 seconds

so, as you can see, the question has to be "how long did the lift take, when it required 400 watts of power ?"

and the answer is "about 3.7 seconds".

NOT about the distance. that was already defined in the first sentence : 6 m.

without knowing the time duration, no distance can be calculated out of the given data. if we cannot trust the given 6m, then we have one equation with 2 variables (distance and time). that has infinitely many solutions.