Question

Ball dropped 40ft and rebounded 1/5 each time. How much it the ball travel before coming to rest.

I need step by step explanation because I really don't understand; I keep getting it wrong.

Answer 1

well this is the infinite sum of 2 geometric series...

the drop down... has a 1st term of 40 and common ratio of 1/5

the bounce up has a 1st term of 8 and a common ratio of 1/5

so you can then use the formula

\[S_{\infty} = \frac{a}{1 - r}\]

here is a diagram

Answer 2

i understand now