Which one of the following conservation laws is a consequence of the Newton’s third law of motion ?
Conservation of energy
Conservation of momentum
Conservation of charge
Conservation of mass
Answer is Wrong!
Answer is Right!
This question was previously asked in
UPSC CAPF – 2023
– When considering a system of two interacting objects, the forces they exert on each other are internal forces. According to the third law, these internal forces cancel out as a pair ($\vec{F}_{\text{AB}} = -\vec{F}_{\text{BA}}$).
– Applying Newton’s second law ($\vec{F} = m\vec{a} = d\vec{p}/dt$) to the system, the total internal force is zero. Thus, the rate of change of total momentum of the system due to internal forces is zero.
– In the absence of external forces, the total momentum of the system remains constant. This is the principle of conservation of momentum.