Acceleration question?

Question

The acceleration due to gravity on the moon is 1/6 th of that on the earth. Imagine that a feather and a hammer are dropped from a height of 1m above the surface of the moon.

a. how long does it take for them to fall to the ground?

b. What is their velocity when they hit the ground?

Please explain.

I am not sure what formula to chose to help me get the answer. How do I know where to input the information once I choose the formula?

Answer 1

You could use this equation for part a:

Distance = 1/2*a*t^2 + vt

But in our case, v = 0 since the initial velocity is zero.  And our "a" will be 1/6 of 9.8 m/s^2, which is gravity on earth.  So our a = 1.63 m/s^2

D = 1/2*a*t^2 + vt   <---vt disappears since v = 0

1 = 1/2*1.63*t^2   <--first we divide all those numbers away

1.227 = t^2   <--now we square root both sides

1.108 s = t

To find their final velocity, remember that velocity = accerlation times time, or...

v = a*t

v = 1.63 * 1.108 = 1.806 m/s

Can someone verify this?  I havent done physics in YEARS.

Good luck.

Goosey