Equilibrium Of Concurrent Forces — the NEET Physics formula with its derivation, variables, validity constraints and worked solver.
Equilibrium of Concurrent Forces Applies to systems where particles are in static equilibrium under the influence of three concurrent forces, or when calculating the resultant/equilibrant of two vectors. Assume a system in equilibrium where the vector sum of forces is zero: F 1 + F 2 + F eq = 0. The equilibrant F eq is equal in magnitude and opposite in direction to the resultant R of F 1 and F 2. Calculate the magnitude of the resultant R using the Law of Cosines for vectors: R = F 1 2 + F 2 2 + 2 F 1 F 2 . Set F eq = R. Forces must be concurrent (acting on the same point). System must be in static equilibrium (net acceleration is zero). Forces must be co-planar for this scalar representation. Confusing the equilibrant force with the resultant force (they are equal in magnitude but opposite in direction). Assuming the angle theta is always 90 degrees. Thinking equilibrium implies no forces are acting, rather than zero net force.