00:00Here are skinny sticks or sticks that have a much greater length compared to their thickness.
00:08The real object of the skinny stick is the wire.
00:14The length of the skinny stick is L.
00:20Suppose the skinny stick is on a two-dimensional surface.
00:26There is a shaft located at a distance d from one end of the stick.
00:30This axis is none other than the z-axis.
00:35That is to say, the stick rotates horizontally.
00:42Based on the concept of moment of inertia, a point particle with mass m and located at a distance r from the axis has a moment of inertia of m r-squared.
00:51How do we determine the r-value in this case?
00:53Is the distance from the shaft to the nearest tip of the stick or d?
01:06Is the distance from the shaft to the middle of the sticks or d plus half L?
01:14Or is the distance from the shaft to the furthest end of the sticks or d plus L?
01:18Which of these three possibilities is true or none of them?
01:26From here, we will get to know the distance dilemma.
01:36Now, suppose that at a distance r from the axis, there are three objects with the same mass but different shapes.
01:45There is a cube.
01:49A sphere.
01:53And a polyhedron.
01:58If these objects rotate, will they all have the same value of moment of inertia?
02:05From here, we will face a form dilemma.
02:12These two types of dilemma will always arise if an object whose mass is continuously distributed rotates about a certain axis.
02:19To get the moment of inertia of an object like this, we can use at least two methods.
02:27The first is the Riemann sum.
02:30The second is integral.
02:34We will discuss this in the next tutorial.
02:39Hopefully this is useful and don't forget to watch the next video.
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