Question regarding finding the magnitude of Torque

[Harikesh_33]

TL;DR

https://imgur.com/a/JDUgrrZ

This is the question ,now there are two ways to approach this .

1)Using the formula τ=r×F .
2)Finding L and differentiating it.

Now I approached the problem with the first method .

Since the mass is moving along a circle of radius rsinθ,the centripetal force is F=mrsinθω² ....(1)

https://imgur.com/a/nZogpVO. ...(A)

Here r is the vector from the centre of rod (which is stationery ) to the mass .

Angle between r and F is 90°+θ .

Therefore Torque τ is rFsin(90+

Question regarding finding the magnitude of Torque of a system of two masses attached to a rod rotating at angle of θ degrees with respect to a vertical

 

[Lnewqban]

What are you considering r to be?

 

[Harikesh_33]

The vector from point through which the rod is rotating to the mass .

I have drawn r Vector in second image .

 

[berkeman]

Thread closed for Moderation...

 

[berkeman]

Thread will remain closed here. @Harikesh_33 -- Please check your PMs. Schoolwork-type questions (even if for self-study) must be posted in the Homework Help forums. Also, please do not just transitory imgur links to the images -- those can disappear which makes your thread make no sense. Please use the "Attach files" link below the Edit window instead. Thank you.