Question

Resultant forces ???????????

Answer 1

Hey there !!!!

Different forces act on a body in different directions.If we combine all these forces resultant force is formed.It is the single force which has the same effect as all forces acting on the body.

             R=F₁+F₂+F₃..............

How to calculate resultant force :

Case 1:

If two forces act on a object in the same direction then sum of those forces will be the resultant force acting on the body.

       R=F₁+F₂

Example : 3N and 4N act on a body in same direction so  
                       resultant force=3+4=7N

case 2:

If two forces act in opposite direction then resultant =F₁-F₂

If 4N and 3N act in opposite direction then 

       R= 4-3 =1N

Case 3:

If two forces F₁ and F₂ make an angle ∅ with each other then resultant force 
              R=(√F₁²+F₂²+2F₁F₂cos∅)

Case 4:

If the forces F₁ and F₂ are mutually perpendicular (∅ =90°)

   R=(√F₁²+F₂²+2F₁F₂*0 )  (cos90=0)

   R=√F₁²+F₂²

Example 3N and 4N are mutually perpendicular 

      R=(√3²+4²)=√25 =5N

Hope this helped you.................

Answer 2

a object remains stationary if the sum of the forces acting upon it - resultant force- is zero