00:01
A wheel with radius 0 .3 meters is free to rotate without friction about a stationary frictionless axis at the center.
00:11
So let's draw the wheel as such and the radius or the distance from the edge to the center is said to be 0 .3 meters.
00:23
Now, the given is the moment of inertia, which is 20 .0 kilogram meter squared.
00:34
And say a tight rope or light rope is wound around the wheel and a constant horizontal force of 40 neutrons is applied.
00:45
So if the rope pulls on the wheel at the edge, at a constant force of 40 neutrons, and if the wheel is initially at rest, what would be the angular speed or omega at time equals 4 .0 seconds after the force is applied? so this is a problem of torque, and we know that torque can be calculated using two approaches.
01:17
The first is via the moment arm, or the lever arm, multiplied by the force.
01:25
Sine theta.
01:27
In this case, the angle between the lever arm and the force is perpendicular or 90 degrees.
01:36
So if you just get sine 90, it would be equal to 1.
01:41
Hence, torque would be equal to the lever arm times the force...