Question

The boy exits the stairwell at the 4th floor, which is 42 ft above the ground. How many seconds will it take him to get to the 4th floor from a height of 136 ft?

Answer 1

Answer:2.41 s

Explanation:

Given

Stairwell is at a height of
`h=42\ ft`

and Height from where he starts
`H=136\ ft`

Total height boy needs to cover is

`=H-h`

`\Rightarrow H-h=136-42=94\ ft`

using

`s=ut+(1)/(2)at^2`

where
`s=displacement`

`u=initial\ velocity`

`a=acceleration`

`t=time`

`here\ initial\ velocity =0`

`94=0+(1)/(2)(32.2)(t)^2`

`t^2=5.83`

`t=2.41\ s`