Unit: energy
Year: 1989 Question#: 24
Question: A spring of negligible mass with a spring constant of 200 newtons per meter is stretched 0.2 meters. How much potential energy is stored in the spring?
(1 ) 40 J
(2 ) 20 J
(3 ) 8 J
(4 ) 4 J
What is this question really asking?
Explanation by: Jill S
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Answer 1
40 J
INCORRECT
40 J is the incorrect answer because you have to use the formula
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Answer 2
20 J
INCORRECT
20 J in incorrect because of the formula that is needed to find potential energy is
, . To get the wrong answer of 20 J you had to of used the formula wrong. One way
that the answer of 20 J could of been found is by not squaring the x, .2 m.return to top
Answer 3
8 J
INCORRECT
.8 J in incorrect because of the formula that is used to find potential energy,
.
To get the answer of .8 J you had to of used the formula wrong. If you did not multiply
by 1/2 you would get .8 J.
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4 J
CORRECT
4 J is the correct answer because of the formula that is used to find the potential energy,
. K= the spring constant, 200 newtons/meter and x=the distance that the spring is
stretched.
PE=1/2(200 N/m)(.2 m)2
PE=4 J
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What's this question really asking?
How much potential energy is in the spring?
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