Inertia, momentum, and conservation of momentum

  1. Inertia is the property of an object to resist changes in its state of motion or rest.
  2. The First Law of Motion, also called the Law of Inertia, states that an object will remain at rest or in uniform motion unless acted upon by an external force.
  3. The Second Law of Motion states that the force acting on an object is directly proportional to the mass and acceleration, i.e., F = ma.
  4. The Third Law of Motion states that for every action, there is an equal and opposite reaction.
  5. Momentum is the product of an object's mass and velocity, defined as p = mv.
  6. Linear Momentum refers to momentum in a straight line, while Angular Momentum involves rotational motion.
  7. Conservation of Momentum states that the total momentum of a system remains constant if no external force acts on it.
  8. The law of conservation of momentum is applied in collisions (elastic and inelastic) and explosions.
  9. In an elastic collision, both momentum and kinetic energy are conserved.
  10. In an inelastic collision, momentum is conserved, but kinetic energy is not.
  11. The unit of momentum is kg·m/s.
  12. Impulse is the change in momentum and is equal to the product of force and the time for which it acts, i.e., Impulse = F × t.
  13. The concept of center of mass is important in understanding momentum in a system of particles.
  14. Impulse-Momentum Theorem relates impulse and momentum change, stating that Impulse = Δp (change in momentum).
  15. If the net force on an object is zero, the object’s momentum remains constant (law of conservation of momentum).

Inertial Reference Frames are those in which Newton's Laws hold true, and there is no acceleration. 

  • In a two-body collision, the total momentum before the collision equals the total momentum after the collision.
  • Elastic potential energy is stored when an object is deformed and is released during motion.
  • Momentum transfer can be used to calculate force during collisions or impacts.
  • In a perfectly inelastic collision, the objects stick together, and maximum kinetic energy is lost.
  • The law of inertia was first proposed by Galileo and later developed by Newton.
  • The momentum of a system is the vector sum of the momenta of all individual components in the system.
  • The velocity of center of mass for a system of particles can be calculated as the weighted average of the velocities of all particles.
  • In a non-inertial reference frame, Newton’s Laws of Motion are not valid without correction terms (fictitious forces).
  • Newton’s Second Law of Motion is applicable in non-inertial reference frames with adjustments for fictitious forces.
  • Force is defined as a push or pull that can change the state of motion of an object.
  • Mass is the measure of the inertia of an object and its resistance to acceleration.
  • The coefficient of restitution measures the elasticity of a collision (e.g., how bouncy an object is).
  • The elastic collision condition is achieved when the relative velocity of approach equals the relative velocity of separation.
  • Inelastic collisions typically involve a loss of kinetic energy, but momentum is conserved.
  • Angular momentum is conserved in systems with no external torques acting on them.
  • Conservation of angular momentum is crucial in understanding systems like rotating planets or figure skaters.
  • The principle of superposition states that the net momentum of a system of particles is the sum of the momenta of each particle.
  • Rotational motion has analogs of linear momentum like torque and angular velocity.
  • The law of conservation of angular momentum applies in closed systems and is key in explaining phenomena like the orbits of planets and objects in free space.
  • Non-inertial frames of reference include systems that are accelerating or rotating.
  • Relativistic momentum differs from classical momentum at speeds approaching the speed of light.
  • The conservation of momentum in explosions refers to the system’s total momentum before and after the explosion being the same.
  • Momentum is a vector quantity, meaning both its magnitude and direction are important.