The Laws of Motion & Force!

Question: What is Inertia?

Answer: The resistance an object has to being moved from rest!

• Inertia is directly proportional to the MASS of an object.

• The more massive an object is, the more Inertia it possesses.

Momentum!Question: What is Momentum?

Answer: The ability an object has to keep on moving in a straight line at constant velocity.

• Symbol:

Momentum is directly related to mass and velocity, so:

p (lower case)

Newton’s 1st Law of Motion!

(also referred to as the Law of Inertia)

Objects at rest tend to stay at rest (Inertia); objects in motion tend to stay in motion, (momentum) at a constant velocity in a straight line, unless acted upon by an unbalanced, external force.

The Laws of Motion & Force!

Question: What is a Force?

Answer: Any influence which CAN cause an object to

accelerate (Push or Pull on an object)

•Forces are vector quantities - you cannot push or pull on an object without doing so in some direction!

The Laws of Motion & Force!

Recall the four fundamental interactions (forces)!Strong force Weak force Electromagnetic force Gravitational force

These are Nuclear Forces and occur at the subatomic level, so their effects cannot be seen with the naked eye. Thus, most people are unaware of them.

These Forces can occur on objects massive enough to be seen, and are readily observable. Gravity is the force responsible for planetary motions and gravitational accelerations. EVERYTHING ELSE is a manifestation of the Electromagnetic Force, i.e. pushes, pulls, surface tensions, electrostatic and magnetic attractions and repulsions, light and radio waves, etc.