Re: [Phys-L] Tennis Ball on Basketball

[John Denker <jsd@av8n.com>]

On 02/23/2017 09:41 AM, Jeffrey Schnick wrote:
> I looked up a solution on the
> internet where it was claimed that you could treat the process as if
> the basketball bounced off the floor and was on its way up by the
> time it collided with the tennis ball which at that time would still
> be on its way down. 
> <https://www.physics.harvard.edu/uploads/files/undergrad/probweek/sol1.pdf
> > This suggests that the timing doesn’t matter.  It seems to me that
> the timing does matter.

Absolutely it matters.

Related fun factoid:  In an ordinary Newton's Cradle device, the
balls at rest are *not* touching ... for exactly this reason.

Rather than solve the general case, which is more work than I
feel like doing at the moment, I suggest rephrasing the question.
Simply /require/ that the two balls be slightly separated.

My guess is that in typical circumstances, aerodynamics will pull
them apart, if dropped from any reasonable height, even if they
were initially together.  However, as always, guesses about fluid
mechanics are worth $1.00e-15.  Also, the fuzz on the tennis ball
might provide sufficient separation.

At any rate, solving the separated case serves as a good warm-up
exercise for solving the general case.