Physics Review Question Unit: energy Year: 1989 Question#: 26 Question: A basketball player who weighs 600 newtons jumps 0.5 meters vertically off the floor. What is her kinetic energy just before she hits the floor? (1 ) 30 J (2 ) 60J (3 ) 300J (4 ) 600J What is this question really asking? Explanation by: Cory V [ Return to question menu ] Answer 1 30Joules INCORRECT Remember that Energy is always conserved, so whatever KE she has just before striking the ground must be equal to the amount of GPE she had at the peak of her leap. Try the GPE=mgh formula, or W =Fs to calculate the work being done. The (600N) is the force multiplied by the displacement which is (.5m). return to top Answer 2 60 Joules INCORRECT Remember that Energy is always conserved, so whatever KE she has just before striking the ground must be equal to the amount of GPE she had at the peak of her leap. Try the GPE=mgh formula, or W =Fs to calculate the work being done. The (600N) is the force multiplied by the displacement which is (.5m). return to top Answer 3 300 Joules CORRECT Using GPE=mgh, you may substitute the players weight (600N) for (mg) and multiply that times the height which is (.5m). The work formula could also have been used. W=Fs return to top Answer 4 600Joules INCORRECT Remember that Energy is always conserved, so whatever KE she has just before striking the ground must be equal to the amount of GPE she had at the peak of her leap. Try the GPE=mgh formula, or W =Fs to calculate the work being done. The (600N) is the force multiplied by the displacement which is (.5m). return to top What's this question really asking? What is the kinetic energy of a basketball player just before hitting the ground, if with a weight of 600newtons she jumped .5 meters? |
[Home] [Lessons] [Review] [Search] [Links]
This web site is designed and maintained by Science Joy Wagon and may
not be reproduced or redistributed without written permission from Science Joy Wagon. |