NEWTON'S LAWS by ALMARIE GHRACE QUIBUAL

Newton’s First Law (Law of Inertia)

24ln0144_ms — 2025-04-03 15:50:16 UTC

Definition: The First Law states that an object will remain at rest or continue to move at a constant velocity unless acted upon by an external force. This is often called the law of inertia.

Inertia: It is the property of matter that resists changes in its motion. The more mass an object has, the more inertia it has, making it harder to change its motion.

Example: Imagine a book on a table. If no one touches it, the book will stay where it is. If someone pushes it, the book will move. If no force acts on it, it will remain stati

onary.

Real-Life Application:

24ln0144_ms — 2025-04-03 15:51:10 UTC

A car that suddenly stops will cause the passengers inside to jerk forward because their bodies want to keep moving in the same direction due to inertia. This is why seatbelts are important—they counteract inertia during sudden stops or accidents.

Newton’s Second Law (F = ma)

24ln0144_ms — 2025-04-03 15:52:19 UTC

Definition: Newton’s Second Law describes the relationship between force, mass, and acceleration. It states that the force applied to an object is equal to the mass of the object multiplied by the acceleration produced. Mathematically, it is represented as F = ma.

Explanation:

If you apply the same force to two objects of different masses, the object with less mass will accelerate more.

If you apply the same force to an object with more mass, the object will accelerate less.

Units:

Force (F) is measured in Newtons (N),

Mass (m) is measured in kilograms (kg),

Acceleration (a) is measured in meters per second squared (m/s²).

Example:

If you push a shopping cart, it accelerates easily (less mass), but if you push a car, it will not accelerate as much (more mass).

If a car is pushing a large object, more force will be needed to move the object.

Newton’s Third Law (Action-Reaction Law)

24ln0144_ms — 2025-04-03 15:52:58 UTC

Definition: Newton’s Third Law states that for every action, there is an equal and opposite reaction. This means that if one object exerts a force on another object, the second object will exert an equal force in the opposite direction.

Explanation:

Forces always come in pairs—action and reaction forces are equal in size but opposite in direction.

These forces act on different objects, so they do not cancel each other out.

Example:

When you jump off a boat, you push the boat backward, and the boat pushes you forward.

In walking, as your foot pushes back on the ground, the ground pushes your body forward.

Real-Life Application:

24ln0144_ms — 2025-04-03 15:53:32 UTC

In sports, athletes use the second law when deciding how hard they need to hit or kick a ball to make it move at the desired speed.

Real-Life Application:

24ln0144_ms — 2025-04-03 15:54:13 UTC

The principle of action and reaction is used in rocket launches. As the rocket expels gas downward, the reaction is the upward movement of the rocket.

Seatbelts and Inertia (First Law):

24ln0144_ms — 2025-04-03 15:55:05 UTC

In the event of a sudden stop (like a car crash), your body wants to continue moving forward due to inertia. Seatbelts apply a force to stop your body from moving forward too quickly, preventing injury.

Pushing Objects (Second Law):

24ln0144_ms — 2025-04-03 15:56:14 UTC

The amount of force needed to push or pull an object depends on its mass. A small object requires less force to move, while a large object (like a truck) requires more force. For example, pushing a car on a flat surface requires much more force than pushing a shopping car

Rocket Launches (Third Law):

24ln0144_ms — 2025-04-03 15:56:49 UTC

Rockets are launched by the action of gases being expelled downwards at high speed. The reaction is the upward motion of the rocket due to the force exerted by the exhaust gases.