A force of 5 pounds compresses a 15-inch spring a total of 4 inches. Calculate the amount of work done in compressing the spring 7 inches.

Answer 1

Hey Ted -

You don't need calculus for this problem - just a couple physics formulas.

To compress or stretch a spring, the amount of work is given by: U_s = 1/2 * k * x²

If you were given k, you could just plug right in, but you were not given k.

To find k, you need to use your other data point, along with the equation F_s = k*x

Solve that for k and then you can go back and plug into the work equation.

The total length of the spring is irrelevant.

Hope this helps,

Chris