Imagine a body with force $F$body and friction force as $F$friction(Friction force is not zero).

When body goes with zero acceleration(no change in speed) $a$object = 0

the net force equation states that:$F$net=$ma$ then we should have net force as 0.(Since $a$=0)

so $F$body=0. But $F$net=$F$friction+$F$body=Ffriction

Which brings the question to mind,why did we calculate net force as zero at first calculation but force of friction as in the second calculation?

Is net force equal to zero or $F$friction?

I'd be happy if you answer my question clearly.


I'm not sure why you are saying that since $F_\text{net}=0$ that $F_\text{body}=0$.

By the definition of net force and by Newton's second law, the net force is $F_\text{net}=F_\text{body}+F_\text{friction}=ma$. If $a=0$ then we have $$F_\text{body}+F_\text{friction}=0$$ i.e. the two forces acting on our object cancel out: $$F_\text{body}=-F_\text{friction}$$


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