Answer:
Explanation:
Given
height of grand canyon is [tex]h=1800\ m[/tex]
Rock is dropped i.e. initial velocity is zero
[tex]u=0[/tex]
Using Equation of motion
[tex]h=ut+\frac{1}{2}at^2[/tex]
h=height
u=initial velocity
a=acceleration
t=time
here a=acceleration due to gravity
[tex]1800=0+\frac{1}{2}\times 9.8\times t^2[/tex]
[tex]t^2=\frac{2\times 1800}{9.8}[/tex]
[tex]t=19.166\ s[/tex]