Question

25.(a) State Newton’s second law of motion. Derive, its mathematical expression. (1+2)

(b) A constant force acts on an object of mass 5 KG for duration of 2 second, it increases the velocity of the 3m/s to 7m/s. Find the force acted on the object. 2

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Answer 1

Answer:

According to Newton's second law of motion, the rete of change of momentum of a body is directly proportional to the force applied on it and the change in moment takes place in the direction in which force is applied...

Equation

Let the force F be applied on a body of mass m for time t due to which it's velocity changes from u to v.

Initial momentum of the body=mu

Final momentum of the body=mv

Change in momentum of the body in t seconds=

mv-mu=m(v-u)

Rate of change of momentum=

Change in momentum/Time=m(v-u)/t

But acceleration a=Change in velocity/time= (v-u)/t

Therefore, rate of change of momentum=

mass × acceleration=m×a

Hope it helps ☺️