Why is a short stick harder to break than a long stick?

Question

Why is a short stick harder to break than a long stick?

In: Physics

Answer 1

It’s because of how stress works in a bending object. To break something, you need to exceed the breaking stress of the material. In a long beam (stick) the stress is much higher for a given torque on the end than a shorter beam. As a result, you need to apply way more torque to a short stick than a long one to exceed the breaking stress, assuming both sticks are the same material.