Hi Chegg, I was just wondering about hooke\'s law (F=-kx) and F_ext, the externa

Question

Hi Chegg,

I was just wondering about hooke's law (F=-kx) and F_ext, the external force needed to stretch the spring a given amount x where Fext = kx. Why is one positive and one negative? I thought hooke's law was for both stretching/compressing, but the way I'm understanding it from my book is that for hooke's law, a compressed spring has a negative x value because you're losing length, making F in hooke's law negative. Then for Fext, it is a positive x because its stretching the spring and adding length x, so Fext is positive. Is that the difference between positive and negative forces in springs?

Thanks!

Ana

Explanation / Answer

The reason is that the restoring force on the srping acts in the opposite direction of the stretch. If you stretch to the left, the force tried to pull it back to the right, and vice-versa.

Related Questions

Navigate

• Browse (All)
• Browse H
• Subjects