Question

After striking the floor a certain ball rebounds (4)/(5)th of its height from which it has fallen. The total distance that the ball travels before coming to rest if it is gently released from a height of 120m is

• A. 960 m
• B. 1000 m
• C. 1080 m
• D. Infinite

Hint:

For rebound problems: Total distance=h+2h((r)/(1-r))

Answer 1

The Correct Option is C

Initial fall distance =120. Rebound ratio r=(4)/(5). Total distance: S = h + 2h(r+r²+r³+⋯) S = 120 + 2(120)(((4)/(5))/(1-(4)/(5))) =120+2(120)(4)=120+960=1080