00:00Hi friends, good afternoon everyone. Thank you for being an active viewer on the Diggus Science channel.
00:11In this series, we will learn about Newton's laws of rotation.
00:17Consider the following object. This is a grinding disk.
00:23Initially, this object is not rotating.
00:26After that, this wheel rotates until it reaches a certain angular velocity.
00:32The object that was originally at rest changes to rotating.
00:36What causes this?
00:40Newton discovered that when an object gets torque, the object will experience angular acceleration.
00:47The presence of this angular acceleration causes the angular velocity of the object to change over a certain time interval.
00:56So, in simple terms, if an object experiences a change in angular velocity, a torque must be acting on the object.
01:10Mathematically, this statement can be written as sigma tau equals I alpha,
01:18where I is the moment of inertia of the object about a certain axis.
01:23This quantity can also be called rotational inertia.
01:28We have known this quantity from the first video in this series course.
01:35Alpha is angular acceleration.
01:38You can understand this quantity in more detail after watching the rotational kinematics course.
01:46Of course sigma tau is the resultant torque acting on an object.
01:52Because it is possible for several torques to act on the same object.
02:00From here, we will find three possibilities.
02:03For non-rotating objects, sigma tau is equal to zero.
02:09This value of zero is a fixed value.
02:12This means that this condition also applies to other constant angular velocities.
02:16Objects rotating at constant angular velocity also have sigma tau equal to zero.
02:31The condition when sigma tau is not equal to zero.
02:36In this condition, the object will rotate with constant angular acceleration.
02:46From this visual illustration, when you see an object rotating,
02:49you will be able to guess whether a torque is working on the object or not.
02:58Hopefully this tutorial is useful.
03:01And, don't forget to watch the next video.
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