Question

Conservation of linear momentum is equivalent to
1. Newton's first law of motion
2. Newton's second law of motion
3. Newton's third law of motion
4. None of the above

Answer 1

Correct Answer - Option 2 : Newton's second law of motion

The correct answer is Newton's second law of motion.

• The linear momentum of a particle is defined as the product of the mass of the particle times the velocity of that particle. 
  • It is a vector quantity and denoted by p.
  • Momentum(p) = mass (m) x velocity (v)
  • Its SI unit is kg-ms^-1.
• According to the conservation of linear momentum, If the net external force acting on a system of bodies is zero, then the momentum of the system remains constant.
• The principle of conservation of linear momentum states that if two objects collide, then the total momentum before and after the collision will be the same if there is no external force acting on the colliding objects.
• The law of conservation of momentum can be explained from the second law of motion. Newton's second law of motion says that the rate of change of linear momentum of a body is equal to the net external force applied to it.
• Newton's second law of motion is defined as the force acting on a body that is directly proportional to the product of the mass of the body and the acceleration produced in a body by the force.
• Force (F) = mass (m) X acceleration (a)
• Example: A person falling on a concrete floor is likely to get more injuries than the one falling on the kaccha floor.
• The launching of rockets works on the principle of conservation of momentum.

• Newton's third law: If object A exerts a force on object B, then object B must exert a force of equal magnitude and opposite direction back on object A. This law represents a certain symmetry in nature: forces always occur in pairs, and one body cannot exert a force on another without experiencing a force itself.
• Newton's first law of motion states that "A body continues to be in its state of rest or of uniform motion along a straight line unless it is acted upon by some external force to change the state".
  • Example: A long jumper runs some distance before taking a long jump.