Question

If a runner exerts 350 J of work to make 175 W of power, then how long did it

take the runner to do the work?
A. 2 sec
B. .5 sec
C. 4 sec
D. .25sec

Answer 1

If a runner exerts 350 J of work to generate 175 W of power, it took the runner 2 seconds to do the work.

Step-by-step explanation:

Power is defined as the speed with which a job is done. In other words, power is a given amount of work done in a given unit of time. That is, it is the amount of work per unit of time that some object or system produces.

Its expression is:

`P=(W)/(t)`

where:

• P: Power developed by the force doing the work. Its unit of measure in the International System is the Watt (W)

• W: Work. Its unit of measure in the International System is the Joule (J)

• t: Time during which the work is carried out. Its unit of measurement in the International System is the second (s).

In this case:

• P= 175 W
• W= 350 J
• t=?

Replacing:

`175 W=(350 J)/(t)`

and solving you get:

`t=(350 J)/(175 W)`

t= 2 s

If a runner exerts 350 J of work to generate 175 W of power, it took the runner 2 seconds to do the work.