# Homework Help: General Launch Angle Problem

1. Sep 22, 2008

### Psiboi

URGENT!!! General Launch Angle Problem

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

A batted baseball leaves the bat at an angle of 25.0 above the horizontal and is caught by an outfielder 370 ft from home plate at the same height from which it left the bat

What was the initial speed of the ball?
How high does the ball rise above the point where it struck the bat?

2. Relevant equations
the 3 acceleration equations

v = vo + at
v^2 = vo^2 + 2a(deltax)
x = xo + vot + 1/2at^2

3. The attempt at a solution

I have tried everything but it seems like this problem is impossible without at least a time or something. This problem isn't a typo tho and there is definitely a solution.

2. Sep 22, 2008

### LowlyPion

Re: URGENT!!! General Launch Angle Problem

Welcome to PF.

Looks to me like you can develop the information you need.

What are the x and y components of velocity. Hint: you have the angle given and the speed.

3. Sep 22, 2008

### Psiboi

Re: URGENT!!! General Launch Angle Problem

i dont see how i was given speed? just the full distance of the ball :(

4. Sep 22, 2008

### razored

Re: URGENT!!! General Launch Angle Problem

Apparently, or maybe not, it seems Vi = 0 m/s ? Problems really should mention it began from rest.

5. Sep 22, 2008

### LowlyPion

Re: URGENT!!! General Launch Angle Problem

No you weren't given the speed. I mistyped. I meant to say you can find the speed from the information given.

Express the velocity in terms of its components. You do know the angle.

Now solve for time. You have two ways to express these velocities with time and distance.

For instance Vy = VSin25 and the time to max height

0 = Vy - g*t

tmax = Vy/g = (VSin25)/g then double that to return to the glove

t(total) = 2*(VSin25)/g

Now you know the equation that expresses distance as a function of time and x-velocity. And you have an expression that gives you time to travel that distance. Solve for V.

6. Feb 9, 2009

### lilqtbabiieo2

Re: URGENT!!! General Launch Angle Problem

I dont understand how to work out this problem at all, how to get the answers.