Newton's 3rd Law
Newton's 3rd Law : Action force and reaction force are equal in magnitude and opposite in direction. āĻāĻžā§°ā§āĻ¯ āĻŦāĻ˛ āĻā§°ā§ āĻĒā§ā§°āĻ¤āĻŋāĻā§ā§°āĻŋāĻ¯āĻŧāĻž āĻŦāĻ˛ āĻ¸āĻŽāĻžāĻ¨ āĻŽāĻžāĻ¨ā§° āĻāĻŋāĻ¨ā§āĻ¤ā§ āĻŦāĻŋāĻĒā§°ā§āĻ¤ āĻĻāĻŋāĻļā§°āĨ¤
Ex:
1. Gun and Bullet
Action: Gun pushes the bullet forward. āĻāĻžā§°ā§āĻ¯: āĻŦāĻ¨ā§āĻĻā§āĻā§ āĻā§āĻ˛ā§ āĻāĻāĻ˛ā§ āĻ ā§āĻ˛āĻŋ āĻĻāĻŋāĻ¯āĻŧā§āĨ¤
Reaction: Bullet pushes the gun backward. āĻĒā§ā§°āĻ¤āĻŋāĻā§ā§°āĻŋāĻ¯āĻŧāĻž: āĻā§āĻ˛ā§āĻ¯āĻŧā§ āĻŦāĻ¨ā§āĻĻā§āĻ āĻĒāĻŋāĻāĻ˛ā§ āĻ ā§āĻ˛āĻŋ āĻĻāĻŋāĻ¯āĻŧā§āĨ¤
2. Walking:
Action: We push the ground backward.āĻāĻžā§°ā§āĻ¯: āĻāĻŽāĻŋ āĻŽāĻžāĻāĻŋāĻ āĻĒāĻŋāĻāĻ˛ā§ āĻ ā§āĻ˛ā§āĻāĨ¤
Reaction: Ground pushes us forward. āĻĒā§ā§°āĻ¤āĻŋāĻā§ā§°āĻŋāĻ¯āĻŧāĻž: āĻŽāĻžāĻāĻŋāĻ¯āĻŧā§ āĻāĻŽāĻžāĻ āĻāĻāĻ˛ā§ āĻ ā§āĻ˛āĻŋ āĻĻāĻŋāĻ¯āĻŧā§āĨ¤
Trick: Newton’s 3rd Law = Action – Reaction pair . āĻ¨āĻŋāĻāĻāĻ¨ā§° āĻ¤ā§āĻ¤ā§āĻ¯āĻŧ āĻ¨āĻŋāĻ¯āĻŧāĻŽ = āĻāĻžā§°ā§āĻ¯–āĻĒā§ā§°āĻ¤āĻŋāĻā§ā§°āĻŋāĻ¯āĻŧāĻž
Formula: F12 = - F21,
Meaning: Action force = Reaction force, Same magnitude, opposite direction
Exam Note: Newton’s 3rd Law = Action – Reaction
