How Do Tension Forces Affect Equilibrium on a Frictionless Surface?

[halpmeplz]

I know that if an object is moving at a constant velocity on a frictionless surface, the forces are balanced (add to 0). The only force vectors you would have are Fg and Fn going down/up.

But what if an object is being dragged across a frictionless surface with a string; wouldn't there be a tension force going left or right? So if you add that tension force, I don't see how the forces in the x-direction can be balanced... because shouldn't there be a force going the opposite way so the forces still add to 0? In a free body diagram, I don't see how there could be a force going opposite the tension force, because there is no friction... so how are the forces still balanced?
Thank you!

 

[Condensate]

If there's no forces acting against the force of the tension force (and it is the only X force,) then what is the net force in the X direction?

The forces don't necessarily have to add to zero on the same object (if they don't, then the net force will cause acceleration on your object instead of allowing its velocity to stay constant.) Although there is technically an equal magnitude of pulling force on the string in the direction of the object.

Does that help to answer your question? :)

 

[halpmeplz]

I think I understand... but I'm only looking at it as if velocity stays constant... in a force diagram, would I draw a force vector going left if I have the tension vector going right? (you said there is a pulling force on the string in the direction of the object)... or would I just have the tension force vector?

edit; I assume the net force would be equal to the tension force...?

 

[Condensate]

On that one object, you would just have the tension vector.

You don't need to worry about the equal force of the object on the string. ;)

 

[halpmeplz]

Ok... thanks so much!

 

[Condensate]

No problem!
If you feel that I was unclear on anything or need further clarification, just PM me.