# Vertical drop of a ball

1. Sep 23, 2010

### TN17

1. The problem statement, all variables and given/known data

You are sitting on the edge of your school with a tennis ball in your hand. Your friend is doing the same thing sitting on the ground leaning against the wall. You both see a toy helicopter going along the line of the second floor. You both decide to take the helicopter down. You both launch your tennis balls in such a way that you hit the helpcopter at the same time.

a) Where is the helicopter when you launch the ball?
b) Where is the helicopter when your friend launches the ball?
c) What is your friend's initial velcoity?

-School is 10 m high
-Windows are 2 m apart
-g = 10m/s2

I'm assuming that my friend is directly below me.

3. The attempt at a solution

For a) I used delta y = Viy*t + 0.5gt2 to find how long it takes for me to drop the ball. Then, if the helicopter's speed is 2m/0.5s, then it would be 4 m along the second floor line in 1 s, when I drop my ball.

For b) I'm not really sure about. I assumed my friend was directly below and had the same answer for a).

For c), I need help with.