Question

Derive the newton first law of motion by using newton second law of motion.

Answer 1

The first law of motion can be
mathematically stated from the mathematical
expression for the second law of motion. is
F = ma
or F =m(v-u)/t
or Ft = mv – mu
That is, when F = 0, v = u for whatever time,
t is taken. This means that the object will
continue moving with uniform velocity, u
throughout the time, t. If u is zero then v will
also be zero. That is, the object will remain
at rest.

Answer 2

Answer:

1. According to Newton's second law of motion, rate of change of momentum is directly proportional to the implied force.
2. From this it follows that is the implied force is zero, there is no change in momentum of the body.
3. Now, momentum = mass × velocity. as the mass of a body is a constant quantity, if there is no change in momentum of the body, the velocity of the body must be constant which may be zero or non zero.
4. Thus, in the absence of an applied force, a body at rest will remain at rest, and a body in uniform motion in a straight line will continue to do so. also, and application of a force, there will be changed in the state of rest or of motion of a body in a straight line. These are the contents of Newton's first law of motion.

Thus, Newton's first law of motion can be obtained from Newton's second law of motion.

Hope it helps :)