Equal Moments at A: Reasoning and Calculation

[NoobeAtPhysics]

Homework Statement

Do the following have equal moments about A?

Homework Equations

T=rf

The Attempt at a Solution

Yes because using L*cos(30), they will be the same?


What is your reasoning?

 

[Tanya Sharma]

Yes because using L*cos(30), they will be the same?

What is your reasoning?

Your reasoning is incorrect ...

τ = r×F

τ = rFsinθ

or τ = r times (component of force perpendicular to line joining A and point of application of force )

So what is τ ?

 

[NoobeAtPhysics]

They both use τ = rFsin30 right? That means they are equal! Right?

 

[Tanya Sharma]

Right...

 

[haruspex]

They both use τ = rFsin30 right? That means they are equal! Right?

"Use" is a strange word there. "Supply" perhaps. Anyway, you asked whether your reasoning was correct, and Tanya S was right in reply, that your reasoning was incorrect (though you got the right answer).