Torque due to reaction force at contact point of two objects

[Rasoul]

Hi there, I would like to know that if we have an leaning object supported by another object, both are supported by ground floor to satisfy static equilibrium condition, does the reaction force at the contact point produce cancelling torque (for the leaning object)? In general, can a reaction force produce torque? If so, is the torque equal to moment arm that is from pivot point to the point the reaction force acting, cross product to the reaction force?

 

[tiny-tim]

Welcome to PF!

Hi Rasoul! Welcome to PF!

Hi there, I would like to know that if we have an leaning object supported by another object, both are supported by ground floor to satisfy static equilibrium condition, does the reaction force at the contact point produce cancelling torque (for the leaning object)?

If you take torques (moments) about the pivot point (on the floor), then yes the torque of that reaction force will be equal and opposite to the torque of the weight (acting through the centre of mass).

In general, can a reaction force produce torque? If so, is the torque equal to moment arm that is from pivot point to the point the reaction force acting, cross product to the reaction force?

Every force produces a torque about any point that's not on its line of action.

And yes, that cross product formula is correct. ​