Essential University Physics: Volume 1 (3rd Edition)

Published by Pearson
ISBN 10: 0321993721
ISBN 13: 978-0-32199-372-4

Chapter 6 - Exercises and Problems - Page 107: 78

Answer

She will not burn of the calories she is claiming to burn off. It would take her $ 4.27 \times 10^4$ reps to burn off the chocolate bar.

Work Step by Step

We calculate how many reps she will need. We use unit conversions to find that the energy is equal to: $=230\times4184=9.6\times10^5 \ J$. Now, we see how many reps, which we will call x, are needed: $9.6\times10^5 \ J=(45)(.5)(x) \\ x = 4.27 \times 10^4$ This is much more than 5, so she will not burn of the calories she is claiming to burn off.
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