Force exerted over a small time and big time frame

[Howlin]

Hi

Why is it that if you hit an object fast it requires less force to break it than if you hit the object slow and applied pressure to it?

 

[A.T.]

If you hit it fast, the forces are higher.

 

[Howlin]

So you are saying if I hit a block of wood or glass really fast, it takes the same force to break it than if i use a force press and it slowly applies force to the block of wood or glass?

 

[russ_watters]

No, he said HIGHER.

However, it may take less impulse (force times time).

 

[Howlin]

No, he said HIGHER.

However, it may take less impulse (force times time).

But why would it be higher, shouldn't it be just the same force required to break the boards or glass, no matter if it is hit fast or slow?

 

[russ_watters]

When you apply a force, the object moves - even when holding it rigidly, it bends. The faster you apply the force, the more of the force that is absorbed by the acceleration of the object.

 

[A.T.]

But why would it be higher, shouldn't it be just the same force required to break the boards or glass, no matter if it is hit fast or slow?

The peak contact force is higher not the force required to break .