A force of 20 N compresses a spring with a spring constant 50 N/m. How much energy is stored in the spring?

4J

Explanation:

Hooke's Law states:

F = -kx

where F = force

k = spring constant

x = displacement of spring

20 = -(50)x

-20/50 = x = -2/5

We can now use this information to find the energy in the Elastic Potential Energy Formula which is...

1/2(k)(x)^2

1/2(50)(2/5)^2 = 4J

0.19 m/s and 0.45 m/s

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