# Projectile Motion

1. Jan 20, 2004

### jjiimmyy101

What do you do to find the x and y coordinates of a ball that is thrown from a building onto a slope?

*Initial velocity is given along with the angle
*The height of the building is given
*And the angle of the sloped ground is given

2. Jan 20, 2004

### Poobel

You should at least try and solve the problem since this place is for help not just asking physisists to solve the problems for you.

No hard feelings

3. Jan 20, 2004

### jjiimmyy101

Equations:
Horizontal Component (a=0): v =vo + a*t; x =xo + vo*t +0.5*a*t^2; v^2=vo^2 + 2*a*(s-so)

Vertical component (a=-9.81): v=vo + a*t; y=yo + vo*t + 0.5*a*t^2; v^2= vo^2 + 2*a*(y-yo)

*(vo)x=12
*(vo)y=16
*t=?
*...

4. Jan 20, 2004

### Poobel

try using

d=Vit+1/2a(t)^2

If your Vi is zero it can work out nicely if you find acceleration

to find acceleration use

Vf^2=Vi^2+2ad work it back assuming you know Vf, Vi and displacement

5. Jan 20, 2004

### jjiimmyy101

I should have been more specific.

Problem: The ball is thrown from the tower with a velocity of 20m/s. Determine the x and y coordinates to where the ball strikes the slope. Also, find the speed at which the ball hits the ground.

**Picture attached

#### Attached Files:

• ###### proj.gif
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6. Jan 20, 2004

### Poobel

The second part is really easy knowing your initial velocity and displacement you should be able to find your final velocity

use Vf^2=Vi^2+2ad where a is acceleration due to earth's gravity and d is your displacement i.e. distance to the ground

first part with the slope though I just simply don't understand -- picture would help a lot

7. Jan 20, 2004

### himanshu121

u need to know the slope

8. Jan 21, 2004

### jjiimmyy101

The picture is in the post above.

"Determine the x and y coordinates to where the ball strikes the slope."

The ball doesn't land on a flat surface. The ground is raised by an angle of 26(degrees) to the horizontal.

I hope that clears it up alittle better.

Last edited: Jan 22, 2004