The discussion revolves around the forces experienced by two positive charges, +q1 and +q2, when one charge (q1) is held still while the other (q2) is free to move. Participants explore the nature of the forces acting on each charge, the implications of holding one charge in place, and the application of Newton's Third Law in this context.
Participants do not reach a consensus on the interpretation of forces acting on the charges, with multiple competing views remaining regarding the nature of the forces and the implications of holding one charge still.
There are unresolved aspects regarding the definitions of net force in the context of multiple objects and the implications of Newton's Third Law, particularly in how forces are perceived in a system of interacting charges.
Since q2 cannot push q1 away, that force does not push q2 away?Mister T said:q2 does not experience a force due to q2.
Whether or not q1 is held in place, the repulsive force exerted on each charged particle is still there. BTW, there's no factor of 2 in the expression for the force.
annamal said:Since q2 cannot push q1 away, that force does not push q2 away?
No, it wouldn't. When q1 is held in place, the net force on q1 is zero. Release q1 and the net force on q1 is ##\frac{kq_1q_2}{r^2}##. The net force on q2 has the same magnitude. The forces act on different objects, so you don't add them together.annamal said:If q1 were let go, the total force would include the factor of 2?
Ok, so the net force of the q1 and q2 charge would be 0 since they exert equal and opposite forces even though there is a net force on q1 and q2 individually?Mister T said:q2 cannot exert a force on itself. It has nothing to do with q1 being held in place.No, it wouldn't. When q1 is held in place, the net force on q1 is zero. Release q1 and the net force on q1 is ##\frac{kq_1q_2}{r^2}##. The net force on q2 has the same magnitude. The forces act on different objects, so you don't add them together.
It's just like me pushing on a block with a force of 10 N. The block pushes on me with a force of 10 N. I don't add them to get 20 N because the forces are acting on different objects.
If they're both free to move then the center of mass does not move - so yes.annamal said:Ok, so the net force of the q1 and q2 charge would be 0 since they exert equal and opposite forces even though there is a net force on q1 and q2 individually?
The net force on q1 is not zero. The net force on q2 is not zero. They exert equal but opposite forces on each other (Newton's Third Law).annamal said:Ok, so the net force of the q1 and q2 charge would be 0 since they exert equal and opposite forces
I mean it is 0 in a system with both q1 and q2 since they cancel.Mister T said:The net force on q1 is not zero. The net force on q2 is not zero. They exert equal but opposite forces on each other (Newton's Third Law).
They do not "cancel". In this context "cancel" means "adds up to zero". But these forces act on different objects. Even if you consider the system consisting of q1 and q2 then the forces are internal. Newton's Third Law requires that forces occur in equal-but-opposite pairs. To say this pair "cancels" is a misconception.annamal said:I mean it is 0 in a system with both q1 and q2 since they cancel.