Question

A feather is dropped on the moon from a height of $1.40$ meters. The acceleration due to gravity on the moon is $1.67m/s^2$. Determine the time for the feather to fall to the surface of the moon. (in s)

• A. $1.29s$
  
• B. $1.2s$
  
• C. $1.9s$
  
• D. $0.29s$
  

Answer 1

The correct option is A $1.29s$

Given, acceleration $a=1.67m/s^2$

Distance covered by feather $d=1.40m$

Initial velocity $u=0m/s$ (assume heather falls from rest)

Using formula $S=ut+a{t}^2/2$,

$1.40=0\left(t\right)+\frac{1}{2}\left(1.67\right)t^2$

or $t^2=2.8/1.67=1.68$

$⟹$ $t=\sqrt{1.68}=1.29s$