Use the impulse-momentum theorem to find how long a stone falling straight down takes to increase its speed from 5.1 m/s to 10.6 m/s ?

Question

Use the impulse-momentum theorem to find how long a stone falling straight down takes to increase its speed from 5.1 m/s  to 10.6 m/s ?

anonymous · Answer

What have you done so far, bro?

anonymous · Answer

Taking down as +
Force = mg
Impulse = change in momentum = (10.6-5.1)m = 5.5m
Impulse = Force x Time => Time = Impulse/force = 5.5/g

You're welcome, feather

anonymous · Answer

I have no idea how to go upon this problem. Thank you for your help!

anonymous · Answer

I figured it out. What I did was... 

(10.6m/s-5.1m/s)= 5.5m/s

(5.5m/s)/(9.8m/s^2)= 0.56 sec

Why feather?