Introduction
Sir Isaac Newton's three laws of motion form the foundation of classical mechanics. These laws describe the relationship between forces acting on a body and its motion due to those forces.
First Law: Law of Inertia
An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
Example: A hockey puck sliding on ice will continue moving until friction and air resistance slow it down.
Second Law: Force and Acceleration
The acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass.
Formula: F = ma
Example: It takes more force to accelerate a car than a bicycle because the car has more mass.
Third Law: Action-Reaction
For every action, there is an equal and opposite reaction.
Example: When you walk, you push backward against the ground, and the ground pushes forward against your foot.
Applications in Space
These laws are crucial for understanding space travel. Rockets work by expelling gas at high speed (action), which pushes the rocket in the opposite direction (reaction).