Question

(a) How long in minutes will the energy in a 963 kJ (230 kcal) cup of yogurt last in a woman doing work at the rate of 130 W with an efficiency of 20.0% (such as in leisurely climbing stairs)? _______min

(b) Does the time found in part (a) imply that it is easy to consume more food energy than you can reasonably expect to work off with exercise?

Yes/No

Answer 1

(a) Answer : 24.7 min

Formula Used :

Power (P) = Energy (E) / Time (t)

so,

or,

Solution :

STEP-1

According to question,

Energy available to do work

= 20% of 9,63,000J

STEP-2

Here,

Using eqn (1) from above,

P = 130 W , E = 1,92,600 J

Putting these values we get,

(b) Yes