A mass attached to the end of a spring is pulled out and released on a surface with friction. The work
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done on the mass by the force exerted by the spring
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never has the same sign as the change in energy owing to friction.
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always has the same sign as the change in energy owing to friction.
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has the same sign as the change in energy owing to friction during one half of each cycle.
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never has the same sign as the change in energy owing to friction if the force of friction is greater than the spring force.
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always has the same sign as the change in energy owing to friction if the force of friction is greater than the spring force.