# Kinetic Energy

1. Dec 2, 2008

### lenbc2006

1. 2) A tennis ball starts from rest rolls down a hill and at the end of the hill becomes airborne. (diagram) Find the horizontal range that the ball drops in.

2. d=v(2h/g)^.5

3. How do you go about solving this problem?

2. Dec 2, 2008

### CompuChip

I don't have the diagram, but I assume that you have some hill given with a downward slope of given angle, and given height.

Well, let's break the problem into two parts.

First, calculate the velocity of the ball at the bottom of the hill (just before it goes airborne). How would you do this?

Then, we can treat the problem as something you have probably seen before, suppose you are standing on a cliff and throw the tennis ball with a velocity v at an angle $\theta$ below the horizontal. How would you find the horizontal distance?

3. Dec 2, 2008

### lenbc2006

ok well i don't know if she is gonna give us the angle and height but if she does i can find the height using h=v^2sintheta /2(g)

4. Dec 2, 2008

### CompuChip

I think you got it backwards.

As I said, as I don't see any diagram, I don't know what information is precisely available, but I think you would at least need the angle and height, so either that should be given or you should be able to calculate it (e.g. horizontal length and length along the slope are given).
Once you have that, you can use the formula you gave to calculate v.
Do you know what all the symbols mean and where the formula came from?