principle of inertia

What is the Principle of Inertia?

It states that an object will maintain its state of motion (constant velocity) unless acted upon by a net external force.

Who first discovered the principle of inertia, and who later incorporated it into the laws of motion?

Galileo discovered it; Newton later incorporated it into his First Law of Motion.

What did Galileo’s ball-on-incline experiment demonstrate about acceleration?

It showed that the ball’s acceleration was constant and depended on the slope angle.

What did Galileo observe when rolling the ball uphill?

The ball decelerated with the same magnitude of acceleration (but opposite in direction) as when going downhill.

What did Galileo conclude about motion on a perfectly horizontal ramp?

The ball would roll with constant velocity forever—demonstrating inertia.

How did Galileo’s principle of inertia contradict Aristotle’s view?

Aristotle believed a force was required to keep an object moving; Galileo showed that no force is needed if there’s no resistance.

State Newton’s First Law.

Every object will remain at rest or in uniform motion in a straight line unless compelled to change its state by an unbalanced external force.

What is the link between force and motion according to Newton?

Newton’s Second Law links force to motion through the relationship F = ma.

What is inertia, and what affects its magnitude?

Inertia is resistance to change in motion; it increases with the object’s mass

What are the characteristics of mass as related to inertia?

Mass is intrinsic, independent of location, velocity, or acceleration.

What four quantities are sufficient to describe motion completely?

Position, displacement, velocity, and acceleration.

How are motion quantities interpreted from graphs?

• Velocity = slope of position-time graph

• Acceleration = slope of velocity-time graph

What does each of Newton’s three laws state briefly?

1. Inertia: Objects maintain motion unless acted on.

2. Force = mass × acceleration.

3. Every action has an equal and opposite reaction.