Answer:2.41 s
Step-by-step explanation:
Given
Stairwell is at a height of [tex]h=42\ ft[/tex]
and Height from where he starts [tex]H=136\ ft[/tex]
Total height boy needs to cover is
[tex]=H-h[/tex]
[tex]\Rightarrow H-h=136-42=94\ ft[/tex]
using
[tex]s=ut+\frac{1}{2}at^2[/tex]
where [tex]s=displacement[/tex]
[tex]u=initial\ velocity[/tex]
[tex]a=acceleration[/tex]
[tex]t=time[/tex]
[tex]here\ initial\ velocity =0[/tex]
[tex]94=0+\frac{1}{2}(32.2)(t)^2[/tex]
[tex]t^2=5.83[/tex]
[tex]t=2.41\ s[/tex]
