# 1 ball hitting Parabola

1. Apr 2, 2009

### Photon713

1" ball hitting Parabola

If a 1" ball hits the inside of a parabola, what part of the ball hits the focal point?
Is it the edge that strikes the inside of the parabola or the center of the ball?
Thank You

2. Apr 2, 2009

### DaveC426913

Re: 1" ball hitting Parabola

What are your thoughts on the matter?

3. Apr 2, 2009

### Photon713

Re: 1" ball hitting Parabola

I think it would be the outer edge of the ball.

4. Apr 3, 2009

### Lok

Re: 1" ball hitting Parabola

I modeled the problem using rhino geometry. Attached 1 pic with a ball crossing the focus.
There is no exact answer.

If the ball follows the parabola axis it will hit dead center (obvious).
But in all other situations, the ball might cross the focus or even miss it completely.
The ball can hit the focus with it's side given certain conditions.

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5. Apr 3, 2009

### DaveC426913

Re: 1" ball hitting Parabola

Cool. But I don't see from your diagram under what circumstances it would miss the focus completely.

6. Apr 3, 2009

### Photon713

Re: 1" ball hitting Parabola

Thank You...

I am attaching an image that represents a 1" ball bearing hitting the inside of a parabola.
Which line represents the passage through the focal point, center or edge? Is the result always the same no matter where the bearing hits the side?

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7. Apr 6, 2009

### Lok

Re: 1" ball hitting Parabola

For ball flying parallel to the axis there are only center to side solutions. But for different angles it is not true. The problem did not specify parallelism though.