00:01
In our question we are given that a solid metal bar is at rest on a horizontal frictionless surface.
00:05
Now it is free to rotate about a vertical axis at the left end.
00:09
We are given the following figures that show forces of different magnitudes that are being exerted on the bar at different locations.
00:16
Now in which case does the bar's angular speed about the axis increase at the fastest rate is what we have to determine.
00:24
Here the concept we are using for our problem is torque.
00:27
Now, initially we use the force and length of a rod to obtain the torque for each given diagram.
00:34
Finally, we use the obtained torque of each rod and compare it with each other to find the correct option.
00:39
Now over here, the torque of an object rotating about its axis is given by the expression tau modulus being equal to r cross f, where f is the force and r the radius.
00:51
Now the torque of an object rotating about its axis is given by equation 1.
00:56
For option a, that is our first diagram, let us substitute l for r and f for the force, we get the talk to be equal to a product of lf.
01:11
Let this be equation 2.
01:13
For option b, we will substitute r to be equal to l by 4 and force being equal to f in equation 1.
01:21
This gives us the talk to be equal to lf by 2.
01:31
Let this be equation 3...