Physics for Scientists and Engineers: A Strategic Approach with Modern Physics (3rd Edition)

Published by Pearson
ISBN 10: 0321740904
ISBN 13: 978-0-32174-090-8

Chapter 11 - Work - Conceptual Questions - Page 302: 12

Answer

The power increases by a factor of 4

Work Step by Step

Let $h$ be the height that the beam was lifted initially. The work done by the motor is equal to the increase in potential energy. That is: $W_1 = mgh$ We can write an expression for the power in the initial case. $P = \frac{W_1}{t}$ Let's suppose that the beam is lifted to twice the height. We can find an expression for the work done by the motor. $W_2 = mg~(2h) = 2~W_1$ We can write an expression for the power in the second case. $P_2 = \frac{W_2}{t/2}$ $P_2 = \frac{4~W_1}{t}$ $P_2 = 4~P$ The power increases by a factor of 4.
Update this answer!

You can help us out by revising, improving and updating this answer.

Update this answer

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.