# Kinematic Problem help

1. Aug 4, 2009

### Toonzaka

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

Determine the initial velocity of a ball which starts 3ft above the ground travels a distance of 180ft and has an angle of 30 degrees; taking into account gravity as 32.2ft/s2.

2. Relevant equations

I have been having trouble as to how to get the time in which it takes the ball to hit the ground. NOTE this is the second part to an impulse question. Which states that a ball traveling 80ft/s is struck by a bat. Impact time of .015s and leaves the bat at a 30 degree angle. I need to know its leaving velocity to find out the Impulse Force...

3. The attempt at a solution

Voy = -32.2t/sin30

Voy2 +64.4*3 = 0

Voy = 13.9ft/s

13.9ft/s = -32.2t/sin30

t = .22s

Vox = 818ft/s

Vo = 818ft/s...

Which does not sound right to me =\

2. Aug 5, 2009

### tiny-tim

Hi Toonzaka!

Sorry, I've no idea what you're doing.

Try again , call the initial velocity v,

so the horizontal and vertical components are vcos30º and vsin30º,

and use the standard constant acceleration equations in both the horizontal and vertical directions (separately).