



 
Hi Bob, On the first drop the ball passes the window once on the way down. On the first bounce the ball rises to $\frac45 \times 10 = 8 \mbox { m }$ and hence the ball passes the window once on the way down and again on the way back up then again on the way down so that's 3. How high does it go on the second bounce? Does it still bounce higher than the top of the window? Eventually it will not bounce high enough to clear the top of the window and on those trips you will only see the ball in the window once, on the way up and the way down. Keep counting and eventually the ball will not bounce high enough to clear the bottom of the window and you won't see it at all. Penny  


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