30 lb 15 30° -u Prob. F2–4

Q: The truss shown below is loaded with P = 300 KN upward vertical load at joint A, supported by a…

A: To determine the horizontal and vertical deflection at point A, we use "The unit load method".…

System of Forces

A force is an external influence or agent that changes the state of a system. According to Newton's second law, the force applied to a body is proportional to the change in momentum of a body. Hence, whenever a force is applied to a body, its momentum changes. If the body is at rest, under the action of force, its state of rest changes to motion. In other words, the magnitude of the momentum of the body changes from zero to a measurable value. Similarly, if the body possesses some initial velocity, it has some associated momentum, the effect of force can cause the body to halt or come to rest, that is, the momentum reduces to zero.