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
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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?

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