Rearranging the Projectile Motion Base Quadratic Formula for Initial Velocity

[Pearlhammer]

Homework Statement

What I'm supposed to do is to rearrange the this formula -16t^2+Vt+h and solve it for V.
V= Initial Velocity t= time (throwing the ball in a parabolic arc) h= height
I know what the height is and it is 6ft. I also have the time which is 2.03 seconds.
How do I rearrange for V? I got an answer but I'm not sure and doubting if it is correct.

Homework Equations

-16t^2+Vt+h

-16t^2+Vt+6 (if you plug in the height.)

The Attempt at a Solution

-16t^2+Vt+6 What I started with

-16t^2+Vt= -6 Subtracted 6 to the other side

Vt= -6+16t^2 Added -16t^2 to both sides.

V= (-6/t)+16t Divided both sides (every term) by t. This is my answer so far.

I have no idea if I'm correct or not and I have the feeling I'm not. Please help, I'm in US grade 9.

 

[Mentallic]

Is that meant to be the physics equation for motion:

[tex]h=Vt+1/2gt^2[/tex] ?

So then re-arranging you have [tex]-1/2gt^2-Vt+h=0[/tex]

It doesn't seem to be consistent with what you started with. But if we assume you started with teh correct equation, yes, you've done it right.

 

[Pearlhammer]

Thank you. What I was talking about was just simply if I had the correct answer for:
Taking -16t^2+Vt+h
and rearranging for V to be by itself on one side of the equation.

 

[ktgster]

-16t^2+Vt+h = 0
-16t^2+Vt = -h
Vt = -h + 16t^2
V = (-h + 16t^2)/t

your right op, but my way is better

 

[Pearlhammer]

Thank you very much guys!

 

[Mentallic]

your right op, but my way is better

How is your way better? It's exactly the same...