How come a bouncing ball does not exhibit SHM characteristics?

[.NoStyle]

Homework Statement

How come a bouncing ball does not exhibit SHM characteristics?

Homework Equations

no clue

The Attempt at a Solution

When I think of SHM, I don't think of contact forces. In the bouncing call case, there is a contact force present when the ball hits the ground.

Would the graph for a bouncing ball look curved as it approached it's height, but then a sharp V as it hits the ground?

Thanks

 

[Defennder]

What is the defining characteristic of a system in SHM? Does this apply to a bouncing ball?

 

[NBAJam100]

Think of it this way...

As the ball bounces, why do the time intervals that the ball is in the air get smaller the longer the ball bounces... it is missing a certain force that is essential to SHM...

 

[Defennder]

The fact that the ball is airborne for shorter periods of times after each consecutive bounce is not the reason why it doesn't count as SHM. One can envisage a hypothetical scenario where the collision of the ball with the floor is entirely elastic; no kinetic energy is lost to the floor as heat, sound etc. There is something more fundamental in the definition of SHM than that consideration.

 

[NBAJam100]

The fact that the ball is airborne for shorter periods of times after each consecutive bounce is not the reason why it doesn't count as SHM. One can envisage a hypothetical scenario where the collision of the ball with the floor is entirely elastic; no kinetic energy is lost to the floor as heat, sound etc. There is something more fundamental in the definition of SHM than that consideration.

maybe were on a different wavelength here, but i was hinting at... its not SHM because it has no restoring force... aka... why the ball doesn't return to its original position. I wasnt saying that's why it isn't SHM, i was using that as an example as to aid him in finding the answer.

 

[LowlyPion]

Homework Statement

How come a bouncing ball does not exhibit SHM characteristics?

Homework Equations

no clue

The Attempt at a Solution

When I think of SHM, I don't think of contact forces. In the bouncing call case, there is a contact force present when the ball hits the ground.

Would the graph for a bouncing ball look curved as it approached it's height, but then a sharp V as it hits the ground?

(By the way, a bouncing ball that is in motion in another direction exhibits what you describe with the sharp V at the impulse of the floor changing direction.

Thanks

From Wikipedia:
"In words, simple harmonic motion is "motion where the force acting on a body and thereby acceleration of the body is proportional to, and opposite in direction to the displacement from its equilibrium position" (i.e. F = − kx)."

Your instinct looks correct. The contact with the floor is an impulse force that perturbs the constant accelerated motion that it is otherwise subjected to in one direction of gravity only.)