i have a question on forces anyone help me

[bettyboopxoxo143]

what condition of forces must prevail for a body, acted upon by a number of forces:
1) to be equilibrium
2) not to be in equilibrium[?]

[Integral]

1) The vector sum of all forces must equal 0
2) The vector sum of all forces not 0

[Tom Mattson]

Originally posted by bettyboopxoxo143
1) to be equilibrium


In addition to the "zero net force" condition, it also must be specified that opposing forces have the same line of action. Otherwise, you could have a force couple acting on an extended object. That would be zero net force, but a nonzero torque, which is not an equilibrium state.

An easy way to include this would be to add to Integral's answer:

1. ...and zero net torque.
2. ...or nonzero net torque.

[NEOclassic]

Originally posted by Tom
In addition to the "zero net force" condition, it also must be specified that opposing forces have the same line of action. Otherwise, you could have a force couple acting on an extended object. That would be zero net force, but a nonzero torque, which is not an equilibrium state.

An easy way to include this would be to add to Integral's answer:

1. ...and zero net torque.
2. ...or nonzero net torque.

Hi Jimmy/Tom,
Don't forget the dipolar loop induced magnetic force that is opposed and equal to the torque in a quantum orbital. Cheers, Jim