Can someone explain Newton's second law In an understandable way for a year 10 student

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jeew-m | College Teacher | (Level 1) Educator Emeritus

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Newton's second law of motion

  • The rate at which momentum change in an object is equal to the net force acting on the object.

Net force acting on object = Rate of momentum change in object

So momentum = mass*velocity

Usually when changing momentum velocity is the most common changing factor since mass is constant most of the times. So then;

Rate of change in momentum = rate of change in velocity


Imagine a situation a ball is rolling on a ground. Lets take it's mass as m and velocity as v1. Then we apply a force on the ball for time of t which result in a velocity change to v2.

So initial momentum of the ball = m*v1

      Final momentum of the ball = m*v2


From the Newtons second law,

Force acting on ball = rate of momentum change

                            = (final momentum-initial momentum)/time

                            = (m*v2-m*v1)/t

                            = m(v2-v1)/t

                            = m*[(v2-v1)/t]

                            = m*a

Where a is accelaration.

Here (v2-v1)/t = rate of change in velocity = accelaration.


So simply speaking we can say that the Newton's second law of motion reveals that force acing on a object is equal to the product of its mass and the accelation due to the force.



The momentum change can be occured even by change in mass.But it is too complex at this grade.