Name:______Date:______
5.4 – Applications of Vectors (Equilibrium)
You've actually already learned about equilibrium, you just didn't know that we were talking about it!
* When the net force acting on an object is zero, the object is in ______.
· Ex: Some situations of equilibrium are easy; others are more difficult, as the following images show.
* When the vector sum of forces acting at one point is not zero, a force can be applied that will produce equilibrium. This force is called the ______.
* To find the equilibrant of two or more forces, first find the ______force. The ______force is equal in magnitude to the resultant but ______in direction.
Example 1: A 10 kg sign is being held up by two wires that each make a 30° angle with the ground. Determine the tension (force) in each of the wires.
· This third force that would do the cancelling out is called the ______.
· The ______ is a vector that is the exact same size as the resultant would be, but the equilibrant points in exactly the opposite direction.
· For this reason, an ______ touches the other vectors head-to-tail like any other vector being added.
Example 2: A net force of 65 N acts due south on an object. What added single force on the object produces equilibrium?
Example 3: Two forces act on an object. One force is 5.0 N horizontally. The second force is 9.0 N vertically.
(a) Find the magnitude and direction of the resultant.
(b) Find the equilibrant force.
Example 4: A sign that weighs 168 N is supported by 2 ropes that make 22.5 angles with the horizontal. The sign is not moving. What forces do the ropes exert on the sign?
Homework Assignment: 1. Read pgs 120 - 122 2. pg 123 # 17 - 22