Question

A feather is dropped on the moon from a height of 10 m. The acceleration due to gravity on the moon is $1.67m{s}^{-2}$​. Determine the time taken by the feather to fall on the surface of the moon.

• A. $3s$
• B. $4.12s$
• C. $3.46s$
• D. $1.41s$

Answer 1

The correct option is C $3.46s$

Given, distance covered (height) $=10m$, acceleration $a=1.67m{s}^{-2}$ and initial velocity, $u=0$
Let the time taken be 't'.
Using the second equation of motion,
$s=ut+\frac{1}{2}a{t}^2$
$10=0+\frac{1}{2}\times 1.67\times t^2$
$\Rightarrow t=\sqrt{\frac{20}{1.67}}$ s
$\Rightarrow t=3.46s$