A.    Finding resultants when angle between forces ¹ 90°

 

 

Ex)    Forces 5N North and 3N 30° S of E act concurrently (on a single point).  

Find the resultant and the equilibrant.

 

When the angle between the forces is not 90 degrees you can't use the Pythagorean theorem or trigonometry

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Answer using the Graphical Method

 

1.    Draw vectors to some invented scale

2.    Make parallelogram

3.    Draw diagonal (resultant)

4.    Find magnitude (ruler and scale)  & direction (angle) of vector

 


Equilibrium - a system is considered to be in a state of equilibrium when its resultant = 0 Newtons

 

 

 

Ex 1)

 

       

                5 N                           5 N

 

At Equilibrium: 

 

¨      F net = 0, a = 0    (F = ma)

¨      Velocity is constant

 

Ex2) Could these forces of 8 N, 6 N and 4 N ever be arranged to produce a state of equilibrium?

 

 

 

 

 

 

 

 

 

If so, find the resultant of the forces 4 and 6.

 

Answer:

 

Ex 3) At the right angle, could these forces be in equilibrium?

 

 

 

 

 

 

 

 


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