A block is initially positioned at height above the ground. There are infinitely many ladder rungs below the block.
Rung is a distance of below the block's starting position. Rung is a distance of below Rung . Rung is a distance of below Rung , etc, etc.
Each time the block hits a rung, it comes to a stop and immediately begins falling again under the gravitational acceleration . The block initially starts falling from its starting position at time .
At what time does the block reach the ground?
Note: Assume that the block's size is negligible
This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try
refreshing the page, (b) enabling javascript if it is disabled on your browser and,
finally, (c)
loading the
non-javascript version of this page
. We're sorry about the hassle.
Time taken to fall h metres = g 2 h
Hence total time :-
t = g 2 ⋅ 2 1 + g 2 ⋅ 4 1 + g 2 ⋅ 8 1 . . .
This can be converted into an infinite G.P sum.
The final answer is t = √ 5 ( √ 2 − 1 ) 1