Question

A body falls from a height of $45$ m above the ground. Find the time taken by the body to reach the ground. $(Takeg=10{ms}^{-2})$

• A. $5$ s
• B. $2$ s
• C. $3$ s
• D. $6$ s

Answer 1

The correct option is C $3$ s

Initial speed $u=0m/s$

Acceleration $a=g=10m/s^2$

Height $h=45m$

Using $h=ut+\frac{1}{2}a{t}^2$

Or $45=0+\frac{1}{2}\left(10\right)t^2$

$⟹t=3s$