4 easy steps to solve any mechanics problem

 

Fundamental concept while solving numerical problem in physics

4  Easy way to solve numerical problem of mechanics -:

there are following steps to solve any numerical problem-:

step 1:- first of all decide the system and draw its F.B.D. ( free body diagram ) separately from the given diagram.

step 2:- write the name of forces acting on it.

Note:- normal force act perpendicular to the surface of body.normal force acts because of contact between the surface of body.It is represented by N       

                

 👉gravity force (mg) alway acts vertically downward to the surface.it acts because of gravitional force of earth. here mass of block M.

👉tension always act in the thread , wire ,rope .or any rod when it is taut .tension always act in the inward direction. here tension in rope given in diagram.

here is a real life pictorial diagram of Tension force on the rope which is taut by two boys . 

step :-4 write the equation of all the forces along  the perpendicular motion ,and make it =0 

i.e. fnet =0. 

along perpendicular motion 

fnet = m*0

fnet = 0

N - Mg =0  

N =  Mg     

and along acceleration direction always take fnet = ma                                                

step :-5  By eliminating any one of variables find the other which is asked in question. 

   Note -:  along acceleration direction  force is taken as +ve.

         opposite to the acceleration direction force is taken as-ve

      forces which is acting in +ve y axis sign of force is taken as +ve

      force which is acting in -ve  y axis sign of force is taken as -ve.

 Example -: 

find tension in the rope and normal reaction ?

soln -:  step 1 - : Decide  a  block of mass M as a  system.

      step 2 -:    Draw the f.b.d. of the block.

   step 3 -: along accleration  

                                           fnet = Ma

 T - Mg =Ma  --- (1)

T  = Mg +Ma

           

 Along perpendicular motion 

  fnet  = 0

 ( N +T ) -Mg =0  

N  = Mg - T

 N = Mg - (Mg +Ma)   {from equation 1}

  N= Mg-Ma        Ans

I hope this will helpful for you .

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suman kumar

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