Question

-> Drive Newton's first law from second law
of motion.​

Answer 1

${\mathfrak{\purple{\underline{\underline{Answer:-}}}}}$

According to Newton's 2nd law of motion:-

F = ma

Assuming that no external force is being applied on the body i.e., F = 0, then,

$\sf{0=ma}$

$\sf{\implies 0 = m\dfrac{(v-u)}{t}}$

$\sf{\implies 0\times m = \dfrac{v-u}{t}}$

$\sf{\implies 0=\dfrac{v-u}{t}}$

$\sf{\implies 0\times t=v-u}$

$\sf{\implies 0=v-u}$

$\sf{\implies v=u}$

According to Newton's 1st law of motion, a body continues in its state of rest or uniform motion in a straight line unless an external force is applied; So, we have proved that v = u.