# The staples inside a stapler are kept in place by a spring with a relaxed length of 0.110 m. If the spring constant is 49.0 N/m, how much elastic potential energy is stored in the spring when its...

The staples inside a stapler are kept in place by a spring with a relaxed length of 0.110 m. If the spring constant is 49.0 N/m, how much elastic potential energy is stored in the spring when its length is 0.140 m?

Answer in units of J

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### 1 Answer

Elastic potential energy is given by

1/2 kx^2

Where k is the spring constant (49.0 N/m)

x is the displacement away from the rest length = Lf - Li = 0.030 m

EPE = 1/2 (49.0 N/m)(0.030 m)^2 = 0.0221 Nm or 0.0221 Joules.

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