Reading Fig. 7.39, total energy is 30 J. At P, potential energy is 20 J giving velocity 6.32 m s-1. At Q, potential energy is 30 J giving velocity 0 m s-1. Point R cannot be reached since it requires ...
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Gravity does negative work upward and positive work downward. Initial kinetic energy is 400 J, while work done by gravity is minus 388 J. The work done by air resistance equals minus 12 J.
The required energy depends on flag mass, gravitational acceleration and pole height. Raising it slowly or quickly does not change the work done. Doubling the lifting speed halves the time, doubling the required power.
The correct filled terms are force and displacement for part one, one for part two, half m v square for part three, m g h for part four and rate for part five respectively.