Question

Which situation describes the highest rate of power?

A. A machine does 200 joules of work in 10 seconds.

B. A machine does 400 joules of work in 10 seconds.

C. A machine does 200 joules of work in 5 seconds.

D. A machine does 400 joules of work in 5 seconds.

Answer 1

Answer : The correct option is, (D) A machine does 400 joules of work in 5 seconds.

Explanation :

Power : It is defined a the rate of doing work per unit time.

Formula used :

`P=(w)/(t)`

where,

P = power

w = work done

t = time

Now we have to determine the rate of power for the following options.

(A) A machine does 200 joules of work in 10 seconds.

`P=(200)/(10)=20W`

(B) A machine does 400 joules of work in 10 seconds.

`P=(400)/(10)=40W`

(C) A machine does 200 joules of work in 5 seconds.

`P=(200)/(5)=40W`

(D) A machine does 400 joules of work in 5 seconds.

`P=(400)/(5)=80W`

From this we conclude that, a machine does 400 joules of work in 5 seconds has the highest rate of power.

Hence, the correct option is, (D)