Question

Please explain newtons law of motion

Answer 1

$\huge\textbf{Newton's Law of Motion :}$

$\textbf{1) Law of Inertia :}$

It is Newton's First law.

According to it an object at rest remains at rest, an object in uniform motion remains in uniform motion until or unless external force applied on them.

==================================

$\textbf{2) Law of Force :}$

It is Newton's Second law.

According to it the rate of change of linear momentum is directly proportional to the external force applied.

F α dp/dt 

F = k dp/dt

Now,

p (momentum) = mv

So,

F = k d(mv)/dt

F = k md(v)/dt

F = k ma

(As, dv/dt = a)

Experimentally k =1

So,

$\textbf{F = ma}$

===================================

$\textbf{3) Action - Reaction Law :}$

It is Newton's Third Law.

According to it, for every action there is equal and opposite reaction. [Equal in Magnitude but opposite in Direction.]

[DERIVATION is in Attachment !!]

$\textbf{F12 (vector) = - F21 (vector)}$

===================================

Answer 2

$\large { \fcolorbox{gray}{black}{ ☑ \: \textbf{Verified \: answer}}}$

Newton 's first law of motion states that a body continues to remain in its rest state or a uniform motion along a straight line endless acted upon by external unbalanced force it is also called Law of inertia.

Newton ' s second law of motion states that external force acting on an object is directly proportional to rate of change of its momentum

Newton 's third law of motion states that every action , there is an equal and opposite reaction .Action and reaction forces act on the different bodies i.e Reaction force = Action Force.