Help with physics problem please.

  • #1
miamirulz29
62
0
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.
 
Last edited:

Answers and Replies

  • #2
miamirulz29
62
0
Anybody?
 
  • #3
harvellt
95
0
sorry
 
Last edited:
  • #4
miamirulz29
62
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I'm not sure what you are asking. Sorry to be such a pain.
 
  • #5
harvellt
95
0
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.
 
  • #6
miamirulz29
62
0
using this equation: Y= Yo + VyoT + 1/2AyT^2, I got 57.151. That definitely is not right or is it?
 
  • #7
harvellt
95
0
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?
 
  • #8
miamirulz29
62
0
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.
 
  • #9
miamirulz29
62
0
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?
 
  • #10
harvellt
95
0
yes that is wrong. That is the Vox, what is the Voy if the ball is thrown horizontally?
 
  • #11
miamirulz29
62
0
zero?
 
  • #12
harvellt
95
0
yep, and then what is the acceleration of the ball?
 
  • #13
miamirulz29
62
0
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!
 
  • #14
harvellt
95
0
no prob!
 

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