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Introductory Physics Homework Help
Why Is My Velocity Calculated Differently than the Solutions?
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[QUOTE="haruspex, post: 6825053, member: 334404"] The question should have made it clear exactly what happens at the bottom of the ramp. If it is a smooth change, with a small arc connecting the two flat surfaces, at least some of the vertical component of velocity will get converted to horizontal. However, the object is shown as a block, so its moment of inertia becomes relevant. To avoid its getting quite messy, take it as a point mass at the centre of a light block. If the radius of curvature of the arc is R its length is Rθ and the normal includes a centripetal component mu[SUP]2[/SUP]/R, which could be a lot more than mg. This gives a frictional force μmu[SUP]2[/SUP]/R acting over that distance and taking away μmu[SUP]2[/SUP]θ of the KE. Note that this cannot be magicked away by making R small. The solution you post assumes a sudden change, and that the vertical component of momentum is simply lost. This immediately takes away ##\frac 12mu^2\sin(\theta) ## of the KE. But the friction complicates matters. There will be an impulse at each end of the block, leading to impulsive friction at each, also instantly reducing the speed. In short, a problem like this with friction is fiendishly difficult. [/QUOTE]
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Why Is My Velocity Calculated Differently than the Solutions?
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