Question

A feather is dropped on the moon from a height of $2m$. The acceleration of gravity on the moon is $1.69{\text{m/s}}^2$. Determine the time for the feather to fall to the surface of the moon.

• A. $2.3s$
• B. $3.2s$
• C. $4.1s$
• D. $1.5s$

Answer 1

The correct option is D $1.5s$

$s=h=2\text{m},g=1.69{\text{m/s}}^2$

Using 2nd equation of motion:
$h=\frac{1}{2}g{t}^2\Rightarrow t=\sqrt{\frac{2h}{g}}t=\sqrt{\frac{2\times 2}{1.69}}=\frac{2}{1.3}t=1.53\text{s}$

Hence the time for the feather to fall onto moon's surface is $1.53s$.