Introductory physics: Chapter 2- Newton's first law of Motion- Inertia

What are two things Galileo discovered?

1. Objects of different weight fall to the ground at the same rate in the absence of air resistance(Free fall)

2. A moving object needs no force to keep it moving in the absence of friction(Inertia)

What is a force?

* push or pull

What is inertia?

• property of matter to resist changes in motion

• depends on mass of object

What was Galileo’s main discovery on his incline experiment?

* He found that if a ball comes to rest, it is due to friction
* Ball moves forever when no force acts on it

What are the two conditions of Newton’s first law of motion state?

1. An object at rest will stay at rest unless acted on by a force

2. An object in motion will stay in motion at constant speed in a straight line unless acted on by a force

What is a vector quantity?

• quantity that has both magnitude and direction

• represented by arrows drawn to scale→ vector

  • Ex: force, velocity, acceleration

What is “T” or tension force?

* force that’s involved with ropes

What is the net force?

* combination of all forces that change an object’s state of motion

What is the equilibrium rule?

* the vector sum of forces acting on a non-accelerating object equals zero

What is equilibrium?

* no change in speed with net force acting = 0

What are the two types of equilibrium?

• static equilibrium- object at rest stays at rest

• dynamic equilibrium- object in motion stays in motion at constant speed