(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A ball is kicked off of a hill with an initial horizontal velocity of 10 m/sec.

The pitch of the hill from where the ball is thrown is -20°. Determine how far the ball lands from its original position.

Not given, but I'm acting under the assumption that gravity = -9.81m/sec²

This is how I see the problem,

http://img78.imageshack.us/img78/6411/projectileeu0.gif [Broken]

2. Relevant equations

a = v/t

d = vo*t + ½at²

3. The attempt at a solution

I would love to say that;

a = v/t

9.81 = 10/t

t = 1.02sec

Then just split and solve so that

d(x) = 10.2, d(y) = -5.1

√(dx² + dy²) = 11.4m

But I can't do that because there is no y velocity so, solving for the only constant.

d = vo*t + ½at²

Split into x,y.

d(y) = -4.905 t²

t = √(d(y)/- 4.905)

d(x) = vo(x)*t

t = d(x)/10

Setting them equal,

d(x)/10 = √(d(y)/- 4.905)

dx = 10√(dy/- 4.905)

dy = - 4.905(dx/10)²

To find thedistance from startuse law cosines, or in this case pythag.

d = √[{10√(dy/- 4.905)}² + {- 4.905(dx/10)²}²]

While this is nice, it isn't getting me any closer to the answer. I need to solve for time somehow...

So... If anyone can give me a nudge it would be extremely grateful.

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Projectile Motion Off a Slope.

**Physics Forums | Science Articles, Homework Help, Discussion**