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Unread 09-01-2014, 10:46
jee7s jee7s is offline
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Re: Friction on the ball

Quote:
Originally Posted by lcoreyl View Post
Also, you should probably take a look at Impulse and its relation a change in momentum. Force is not the only thing to think about.[/url]
I concur. This is either an energy or momentum problem.

If you do it as a momentum problem, you need to determine the impulse necessary (m * v = F * (delta t)) to get the ball going fast enough to be on a trajectory to score or get over the truss. So, large force for short time or small force for long time.

From a spatial perspective, energy provides a more convenient model ((1/2) * m * v^2 = F * d). So, apply a large force over a short distance or a smaller force over a long distance.

Either way, you need to account for the aforementioned friction and drag losses. If you pick a spring that stores just enough energy to give the ball the velocity for your desired trajectory, you will be short. You'll be losing energy to friction, drag, and other un-modeled inefficiencies. So, you can get a good guess with some high school physics, but to refine that requires simulation or testing or both.
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