# Help with projectile motion

1. Jan 21, 2013

### helpme2012

Help with projectile motion :(

1. The problem statement, all variables and given/known data
A soccer ball is kicked from the roof of a 260m building. The ball is given an initial speed of 22m/s. It is airborne for a period of 8.3s and travels horizontally for 165.5m before hitting the ground. What is the angle ( in degrees) at which the soccer ball was kicked?

2. Relevant equations
No idea :(

3. The attempt at a solution
I don't even know where to begin

Last edited by a moderator: Jan 21, 2013
2. Jan 21, 2013

### apelling

Re: Help with projectile motion :(

Then think about components of velocity.

3. Jan 21, 2013

### helpme2012

Re: Help with projectile motion :(

I honestly have no idea what I'm doing on this question. I'm completely lost.

4. Jan 21, 2013

### apelling

Re: Help with projectile motion :(

Horizontally the ball moves 165.5m in 8.3s. What is the horizontal speed?

5. Jan 21, 2013

### helpme2012

Re: Help with projectile motion :(

19.94m/s

6. Jan 21, 2013

### apelling

Re: Help with projectile motion :(

19.94 is a component of the initial 22m/s.
Draw a right angled triangle with 22 on the hypotenuse, 19.94 on the adjacent side and work out the angle.

7. Jan 21, 2013

### helpme2012

Re: Help with projectile motion :(

24.99 degrees, rounded off to 25 degrees.

8. Jan 21, 2013

### apelling

Re: Help with projectile motion :(

Yep that's the right answer. That is all that was needed.

9. Jan 21, 2013

### helpme2012

Re: Help with projectile motion :(

Hah, I got that before when playing around with Δdχ= VixΔt
You're awesome, I'm an idiot lol. Thanks :)

10. Jan 21, 2013

### HallsofIvy

Staff Emeritus
Re: Help with projectile motion :(

Why did you erase the question? This thread might have helped other people.

11. Jan 21, 2013

### Staff: Mentor

Re: Help with projectile motion :(

I fixed it.