<p>why can't a ball on a string on the end of a stick swing so that the cord remains exactly horizontal?</p>
<p>because there will always be gravity pulling it down.</p>
<p>ahh right. so how do you find the angle the cord makes with the horizontal?</p>
<p>can you give us a diagram?</p>
<p>hmm... i don't know how to actually get a diagram on here, but i can try to explain it better. </p>
<p>It's just a vertical pole, with a string coming out horizontally from the top. The string is rotating in a circle and has a ball attatched to the end. I need to find the angle the string makes with the line perpendicular to the pole.</p>
<p>This isn't rigorous, but here's a method that will work:</p>
<p>Construct a right triangle, with the string as the hypotenuse, and the line perpendicular to the pole as the leg adjacent to the angle, phi, in question. Drop a vertical line from the adjacent leg to the hypotenuse, and let this line be the leg opposite to phi.</p>
<p>Denote the adjacent side A, and the opposite side O; denote the hypotenuse H. Then, the ratio O / A will be equal to the ratio of the centripetal force on the ball and the gravitational force on the ball.</p>
<p>This ratio of forces can be written as (mv^2 / r) / (mg) = v^2 / rg. Hence, O / A = v^2 / rg. Notice, however, that O / A is the tangent of phi. Finally, then, phi = arctan(v^2 / rg).</p>
<p>I think that this will work - correct me if I'm wrong, though.</p>
<p>Ewww....physics. Gross.</p>
<p>sorry, I despise science.</p>
<p>Anyways, carry on.</p>
<p>no physics is really good
i cant do physics without the diagram..darn it :mad:</p>
<p>haha well i have to agree with ihateCA... physics is pretty much the bane of my existance.</p>