# Help with physics problem please.

Projectile Motion and Level Horizontal Range.

## Homework Statement

The acceleration of gravity is 32ft/s ^2.
If a pitch were thrown horizontally with a velocity of 96.9 mi/h, how far would the ball fall vertically by the time it reached home plate, 60ft away. Answer in units of ft.
So speed is 142.12 ft/s.

## Homework Equations

Vx = Vxo + Axt
Y= Yo + VyoT + 1/2AyT^2 or Vy^2 = Vyo^2 + 2Ay(Y-Yo)

For the second equation, don't know which one to use.

## The Attempt at a Solution

I got the time it took to reach 60 feet by using the first equation. T= 4.441. I don't know where to go from there. I think I use this equation: Y= Yo + VyoT + 1/2AyT^2

but I'm not sure. Any help would be appreciated greatly.

Edit: actually t= .422 seconds.

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Anybody?

sorry

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I'm not sure what you are asking. Sorry to be such a pain.

Sorry, ok so you know how long it takes for the ball to get from release to home. It travels a distance in the -y direction in that time. Thats what your looking for.

using this equation: Y= Yo + VyoT + 1/2AyT^2, I got 57.151. That definitely is not right or is it?

probably not what are you using for Vy at t=0? and if y=0 at the pitchers release what direction is acceleration in the y direction?

I cannot figure out this problem. Maybe I got the time wrong. I don't even know what I'm looking for. Can somebody please clarify some stuff for me. I just want to know how to do it.

probably not what are you using for Vy at t=0?

You mean Vyo, I used the original speed the ball was thrown, 142.12 feet/s. Is that wrong?

yes that is wrong. That is the Vox, what is the Voy if the ball is thrown horizontally?

zero?

yep, and then what is the acceleration of the ball?

OMG I just got it. Voy is 0! So it is -y = 1/2 (32) (.422)^2. Which gives me 2.849. Which is right in the computer. Thank you for your help!

no prob!