00:01
Question we are given the mass of a grindstone m is equal to 90 kilogram and the value of radius of this are equal to 0 .34 meter and the value of angular speed of this omega equal to 90 revolution per minute so converting this to radiance per second we will be getting 9 .42 radian per second okay so now value of radial force acting on the disk f is given as 20 newton using all this in first part of the question we need to find the value of angular acceleration angular acceleration is given by alpha is equal to tau by i that is tarp by moment of inertia so first let us found the value of torque tau so tau can be found using r into f and the value of r here is 0 .34 and the value of f can be found using new into n okay so now 0 .34 into new value is 0 .2 into n value is 20 newton okay so normal force only we are given here 20 new 10 so solving all this will be getting the value of tar tau will be equal to 1.
01:28
0 .36 newton meter.
01:33
So now value of moment of inertia, let us find, i is equal to half m r square.
01:40
So 1 by 2 into m value is 90 kg into r value is 0 .34 the whole square.
01:49
Solving this, we get the value of moment of inertia, i is equal to 5 .202.
01:56
So now the angular acceleration, which will be equal to tau by i can be written as 1 .36 divided by 5 .202.
02:08
Okay, solving this we get the value of angular acceleration will be equal to 0 .26 radian per second.
02:19
It will be part of the question.
02:21
Let teta are the number of turn made by the stone.
02:25
Okay, we need to find the value of teta only.
02:27
So using equation of rotational kinematics we can write theta that is number of turns made by the stone will be is equal to omega -f minus omega -i divided by 2 alpha...