Does normal contact force exert torque?

AI Thread Summary
In the discussion about whether normal contact force exerts torque, it is clarified that the normal force acts perpendicular to the surface and does not necessarily pass through the center of mass of the object. This means that while the normal force can exert torque, it depends on the point of application and the distance from the center of mass. The torque due to the normal force can be calculated as the vector product of the normal force and the perpendicular distance from the point of contact to the center of mass. Additionally, the normal force plays a crucial role in preventing collisions between touching bodies by adjusting its magnitude and position. Overall, the normal force can indeed exert torque under certain conditions.
Sharp2
Messages
2
Reaction score
0
I came across a question in which a cubical body of mass 'm', edge 'a' is slipping down an inclination with constant velocity and torque due to normal contact force is to be found about the centre of the block.
As friction will exert an anticlockwise torque= 0.5amgsinx, where 'x' is the inclination, I was told that the normal contact force will exert an equal and opposite torque to keep the body in rotational equilibrium.
But doesn't normal contact force pass through the centre of the body? Then how can it possibly exert a torque?
 
Physics news on Phys.org
But doesn't normal contact force pass through the centre of the body?
Nope.

The normal force is called "normal" because it acts along a line perpendicular to the surface, i.e, along the normal. This line need not pass through the bdy's center of mass (or, for that matter, its geometric center).

The normal force "prevents" collision&interpenetration of two touching bodies and will, therefore, arrange itself in such a manner (in terms of magnitude&position where it acts) so that these collisions won't happen.

This will always be a success, until the internal stress in one (or both) surface(s) becomes too great, and a rupture/fracture occurs.
 
Thanks! I came across another question in which the normal force acts along the corner of the cube (to find the condition for toppling and sliding)! Thank you. =)
 
normal can exert torque
consider a case in which a disc is kept on an inclined plane
 
The torque due to normal reaction is the vector product of the normal reaction it self &the perpendicular distance between point of contact and center of mass.
 
Thread 'Is 'Velocity of Transport' a Recognized Term in English Mechanics Literature?'
Here are two fragments from Banach's monograph in Mechanics I have never seen the term <<velocity of transport>> in English texts. Actually I have never seen this term being named somehow in English. This term has a name in Russian books. I looked through the original Banach's text in Polish and there is a Polish name for this term. It is a little bit surprising that the Polish name differs from the Russian one and also differs from this English translation. My question is: Is there...
Thread 'Beam on an inclined plane'
Hello! I have a question regarding a beam on an inclined plane. I was considering a beam resting on two supports attached to an inclined plane. I was almost sure that the lower support must be more loaded. My imagination about this problem is shown in the picture below. Here is how I wrote the condition of equilibrium forces: $$ \begin{cases} F_{g\parallel}=F_{t1}+F_{t2}, \\ F_{g\perp}=F_{r1}+F_{r2} \end{cases}. $$ On the other hand...
Back
Top