Question
Den pushes a desk 400 cm across the floor. He exerts a force of 10 N for 8 s to move the desk. What is his power output? (Power: P=W/t 1.25 W 5W 40 W 500 W
Answer
4.1
(303 Votes)
Emily
Master · Tutor for 5 years
Answer
5 W
Explanation
To determine Den's power output, the work done (W) needs to be calculated first, and then use the power formula
, where
is power,
is work done, and
is the time over which the work is done.1. Calculate the work done. Work done
is the product of the magnitude of the displacement over which the force is applied and the component of the force acting in the direction of the displacement. So, if force (
) is 10 N and displacement (
) is 400 cm, or
. But we need to convert 400 cm to meters by dividing by 100, since in SI units, work is in joules, force is in newtons, and displacement is in meters.2. Calculate the power using the formula
once
is found from the above step. Time
given is 8 seconds.To summarize, the process is:- Convert displacement from cm to m.- Compute the work done,
, after conversion.- Calculate the power output,
.