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sol15 - unchanged Therefore you can change an object’s...

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PHYSICS 103 Chapter 7 -- HW #15 Questions 4. Momentum and energy are entirely different quantities, so it makes no sense to say one is bigger than the other. This would be similar to saying that a person is taller than his weight. 12. Kinetic energy does not depend on direction and is therefore constant. The length of the momentum vector is constant but, as the jet’s direction changes, so does the direction of its momentum vector. Therefore, the momentum is not constant. 26. Because momentum is a vector quantity, you can change an object's momentum by simply changing its direction. If you do not change the object’s speed, its kinetic energy is
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Unformatted text preview: unchanged. Therefore, you can change an object’s momentum without changing its kinetic energy. On the other hand, when you change the object’s kinetic energy, you must change its speed. Because the magnitude of its momentum depends on the speed, you must therefore also change the momentum. Exercise 10. This is an application of the work-energy theorem. Remember that friction does negative work and decreases the kinetic energy. net f i W F x KE KE KE = ∆ = ∆ =-( 29 ( 29 12 J 0.6 N 5 m 9 J f i i KE KE W KE fd = + =-=-=...
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