Question

What is resultant force? Give examples.

Answer 1

When there is more than one force acting upon the same body. The different forces is altogether replaced by a single force. This force is called resultant force.


The formula of resultant force is F∨R = F∨1 + F∨2 + F∨3
If the force F∨2 is perpendicular to the force F∨1 then the formula is 
F∨R = F∨1 + F∨3 - F∨2 



EXAMPLE --
If three forces 60N , 45N and 30N are acting on a body simultaneously. 30N is opposite to the direction of other two. Calculate the resultant force.

SOLUTION -- 
As per the formula we will place the quantities. 

(60N + 45N) - 30N 
105N - 30N
= 75N

Hence, the resultant force for the question asked is 75N.


#hope this helps u ...
#Thnx...

Answer 2

Hey there !!!!

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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

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