Physics: Principles with Applications (7th Edition)

Published by Pearson

Chapter 6 - Work and Energy - Problems: 18

Answer

$-3.2 \times 10^{5} J$.

Work Step by Step

The net work done on the car is the change in its kinetic energy, by equation 6–4. The final KE is zero. The initial speed is 26.4 m/s. $$W = \Delta KE = 0-\frac{1}{2} mv^{2}$$ $$W = -\frac{1}{2} (925 kg)(26.4 m/s)^{2}=-3.2 \times 10^5 J$$ The work is negative because the car slows down. The answer is rounded to two significant figures.

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