Essential University Physics (3rd Edition)
3rd Edition
ISBN: 9780134202709
Author: Richard Wolfson
Publisher: PEARSON
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Chapter 7.4, Problem 7.4GI
For which of the following systems is (1) mechanical energy conserved and (2) total energy conserved? (a) the system is isolated, and all forces among its constituents are conservative; (b) the system is not isolated, and work is done on it by external forces; (c) the system is isolated, and some forces among its constituents are not conservative
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At time ti, the kinetic energy of a particle is 30.0 J and the potential energy of the system to which it belongs is 10.0 J. At some later time tf , the kinetic energy of the particle is 18.0 J. (a) If only conservative forces act on the particle, what are the potential energy and the total energy of the system at time tf ? (b) If the potential energy of the system at time tf is 5.00 J, are any nonconservative forces acting on the particle? (c) Explain your answer to part (b).
Is it possible for the total mechanical energy of a moving particle to be negative?
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Only if friction is involved.
No, because potential energy cannot have a value more negative than the value of the positive kinetic energy of the particle.
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Chapter 7 Solutions
Essential University Physics (3rd Edition)
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