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a certain ball is dropped from a height of x feet. Suppose the ball is dropped from 10 feet and is caught exactly when it touches the ground after the 30th bounce, what is the total distamce traveled by the ball? Explain you r answer in exponential notation

 Sep 24, 2014

Best Answer 

 #1
avatar+129840 
+5

We can't give a definitive distance, because it depends upon the rebound height  of the ball. We can model the situation as follows:

The ball travels 10 ft and then strikes the ground. It then rebounds to a height of 10r, where r is  some value between 0 and 1. And it falls this distance again before striking the ground.

So, the ball has traveled 10 + 2*10r feet.

And on the next bounce it rises to a height of (10r)r = 10r2 feet ..and it also falls this far before striking the ground again.

So, after two bounces, the ball has traveled  10 + 2*10r + 2*10r2  feet = 10 + 20 (r + r2) feet

So, the total distance traveled after 30 bounces is just  10 + 20(r + r2 + r3 +......+ r29 + r30) feet

And we can rewrite this as:     -10 + 20 (1 + r + r2 + r3 +......+ r29 + r30 )  ...  and this can be simplified to.......

Total Distance  =  -10 + [ 20 / (1 - r) ]  where  0 < r < 1

 

 Sep 25, 2014
 #1
avatar+129840 
+5
Best Answer

We can't give a definitive distance, because it depends upon the rebound height  of the ball. We can model the situation as follows:

The ball travels 10 ft and then strikes the ground. It then rebounds to a height of 10r, where r is  some value between 0 and 1. And it falls this distance again before striking the ground.

So, the ball has traveled 10 + 2*10r feet.

And on the next bounce it rises to a height of (10r)r = 10r2 feet ..and it also falls this far before striking the ground again.

So, after two bounces, the ball has traveled  10 + 2*10r + 2*10r2  feet = 10 + 20 (r + r2) feet

So, the total distance traveled after 30 bounces is just  10 + 20(r + r2 + r3 +......+ r29 + r30) feet

And we can rewrite this as:     -10 + 20 (1 + r + r2 + r3 +......+ r29 + r30 )  ...  and this can be simplified to.......

Total Distance  =  -10 + [ 20 / (1 - r) ]  where  0 < r < 1

 

CPhill Sep 25, 2014

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