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 : 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 :

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.

(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.

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)

causes

fossil fuels burn

cities become more industrialized

human population grows worldwide

the answer is c. the lower legs are levers, and the knees are fulcrums. the ankles hold the loads.