AP Physics - presentation L2.8 spring force.pptx

AP Physics -

1. L2.8 Spring Force ( Hooke’s Law )

2. Springs Springs are useful because they exert a restoring force when stretched or compressed. Hooke’s Law states that a spring’s force increases linearly with the length the spring is stretched or compressed: F = k ∆ x The constant k is called the spring constant . The larger k is, the smaller the ∆x for a given F . Similarly, the more force you pull a spring with, the farther it will stretch.

3. Springs Hooke’s Law: F = k ∆ x This is why the gradations on a spring scale are spaced evenly. What are the SI units of the spring constant, k ?

4. Example Hooke’s Law: F = k ∆ x

5. Mini-Lab Calibrate 2 spring scales, put them together horizontally, and pull apart. Do they always show the same force? What are they measuring? Put 2 spring scales together vertically, and calibrate both to zero. If a weight is added at the bottom, will both scales show that weight, or half that weight? Why?