Set6_Lecture_10_22_2007

Just before hitting the ground what is the kinetic

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Unformatted text preview: a cliff. Just before hitting the ground, what is the kinetic energy of the heavy stone compared to the light one? compared to the light one? 1) quarter as much 2) half as much 3) the same 3) the same 4) twice as much 5) four times as much Consider the work done by gravity to make the stone fall distance d: ΔKE = Wnet = F d cosθ ΔKE = mg d Thus, the stone with the greater mass has the greater KE which is twice KE, which is twice as big for the heavy stone. big for the heavy stone FollowFollow-up: How do the initial values of gravitational PE compare? ConcepTest ConcepTest 6.3 Slowing Down If car traveling 60 km/hr can If a car traveling 60 km/hr can brake brake to a stop within 20 m, what m, is its stopping distance if it is traveling 120 km/hr? Assume km/hr? that the braking force is the same in both cases same in both cases. 1) 20 m 2) 30 m 3) 40 3) 40 m 4) 60 m 5) 80 m ConcepTest ConcepTest 6.3 Slowing Down If car traveling 60 km/hr can If a car traveling 60 km/hr can brake brake to a stop within 20 m, what m, is its stopping distance if it is traveling 120 km/hr? Assume km/hr? that the braking force is the same in both cases same in...
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