Forces and Newton’s Laws

Galileo

• 1st to state that forces are not necessary to keep things moving

• In the absence of friction, things will continue to move if already moving and stay at rest if already at rest

• Every material has a resistance to a change in its state of motion - INERTIA

An inertia example

Newton’s 1st law. (The law of Inertia)

• Every body continues in its state of rest, or of constant motion in a straight line at a constant speed, unless it is compelled to change that state by an unbalanced FORCE

Demonstrations

I HOOP IT WORKS?

HOW’S IT HANGING?

Question.

• Would it be correct to say that the reason an object resists change, and persists in its state of motion is because of inertia?

Bad Inertia

•Jumping to Breinigsville•Helicoptering to

California

Inertia example

A painful inertia example

Fact• If an astronaut is in space for any

extended period of time, it is extremely important that He or She does not lose mass. How can an astronaut measure his or her mass while in a “weightless” environment?

An objects inertia is measured by its MASS

Mass VS Weight

• Mass• Amount of matter in

an object• Does not depend on

location

• Weight• The gravitational

force that acts on an object

• Depends on location

Mass and weight are not the same, but are proportional to each other in

any one location

…unless it is compelled to change that state by anUNBALANCED FORCE