Condition when the body is in
(i) Dynamic equilibrium …. the body should remain in its state of uniform motion when it is under the action of forces.
Example : A train running with a constant speed is in dynamic equilibrium, because the force generated by its engine is equal to the force of friction due to rails and force of friction due to air.
(ii) Static equilibrium : The body should remain in state of rest when it is under the action of forces.
Example : When a body is at rest on the ground the various forces are : W = R and F = F
