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A particle is inside a smooth conical envelope rotating at a certain speed. If the particle is 45 centimeters from the axis of the cone, what is its velocity?

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Transcript
00:00Hi friends, a. Be a knowledgeable person who educates others.
00:05Be an intelligent person who makes others intelligent.
00:09A successful person who makes others successful.
00:13A conical shell rotates at a certain angular velocity.
00:18A particle is on the inner surface of the cone.
00:22We are asked to calculate the magnitude of the particle's velocity so that the particle does not move relative to its original position.
00:30Problems like this require imagination.
00:35How about we watch this animation for a moment?
00:40It is not easy to draw the inner surface of the conical shell.
00:45A particle is on the color boundary line.
00:50What is important to note is that the surface is smooth.
00:55Of course, the particle will move in a straight line toward the apex of the cone.
01:00In our case, the cone is rotating at a certain angular velocity.
01:08The particle on the surface also rotates with the cone.
01:14During this process, the particle remains on the boundary line.
01:17This means that the particle is not actually moving at all relative to its initial position.
01:26However, a stationary observer outside the cone sees the particle rotating about the cone's axis.
01:32This linear velocity is what we want to calculate.
01:35I think this animation is clear enough.
01:41Now we will identify the forces acting on the particle.
01:43Particles have mass and they are attracted toward the center of the earth by the force of gravity.
01:52The particle touches the surface of the cone and the normal force acts in the normal direction.
02:00It seems there are no other forces besides these two.
02:07The particle's trajectory is circular.
02:10We can say that the particle is in circular motion.
02:16The force that causes the particle to move around the axis is the centripetal force.
02:20However, unfortunately, there is no such force.
02:25We must decompose the normal force into its component vectors.
02:31It is clear that N sine theta is directed towards the center of the circle.
02:36This is the force that contributes to the centripetal force.
02:41Simply write N sine theta is equal to MV squared over R.
02:46R here is the distance from the particle to the axis of rotation.
02:50We don't yet know the values of N and V, so we need one more equation.
02:58Since the particle isn't moving in a vertical direction, the resultant force in that direction is 0.
03:05N cosine theta minus MG equals 0.
03:10We can write this equation as N cosine theta equals MG.
03:17To eliminate N, we can divide the two equations.
03:20Sine over cosine is tangent.
03:29From here, AV equals root RG tangent of theta.
03:35It looks like all the values on the right-hand side are already written on the worksheet.
03:39V is about 1.5 meters per second.
03:42Happy studying, everyone.
03:47Happy studying, everyone.
03:47Happy studying, everyone.
03:47Happy studying, everyone.
03:48Happy studying, everyone.
03:48Happy studying, everyone.
03:49Happy studying, everyone.
03:49Happy studying, everyone.
03:50Happy studying, everyone.
03:51Happy studying, everyone.
03:52Happy studying, everyone.
03:53Happy studying, everyone.
03:54Happy studying, everyone.
03:55Happy studying, everyone.
03:56Happy studying, everyone.
03:57Happy studying, everyone.
03:58Happy studying, everyone.
03:59Happy studying, everyone.
04:00Happy studying, everyone.
04:01Happy studying, everyone.
04:02Happy studying, everyone.
04:03Happy studying, everyone.
04:04Happy studying, everyone.
04:05Happy studying, everyone.
04:06Happy studying, everyone.
04:07Happy studying, everyone.
04:08Happy studying, everyone.
04:09Happy studying, everyone.
04:10Happy studying, everyone.
04:11Happy studying, everyone.
04:12Happy studying, everyone.
04:13Happy studying, everyone.
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