Saturday, 12 December 2015

newtonian mechanics - Explanation on Newton's second law



I have asked a question on I pushing the wall,where the force of me is not zero but as per the formula F=m.a,the force is zero and then I got the answer , it is because here the net force is acting on the body.But I a doubt that then a body of mass 5kg and moving with an acceleration 2m/s^2 will experience a force = 10N,Is in this case also the net force acting? Or the net force is acting only when the body doesn't move? If this is correct then my question why?



Answer



Now starting from scratch, what we know from Newton's 2nd law is given below:-$$\vec{F_{net}}=m\vec{a}$$


When we push the wall the forces acting on it are:- 1) Friction in opposite direction of your push. 2)Your pushing force. 3)Normal reaction from earth. 4)Weight. 5)Downward normal reaction from ceiling. As,$$\vec{a_{net}}=0$$ $$\vec{f}+\vec{N_{e}}+m\vec{g}+\vec{N_{c}}+\vec{F_{you}}=0$$ I think these two equations in itself describes the whole mechanics of the problem.


Hope this helps!


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