Learn: Chapter 3- Newton's First Law of Motion- Inertia

Aristotle divided motion into two types ______ and ______.

natural

violent

Natural motion on Earth was once thought to be either ________ or _______.

straight up

straight down

Aristotle thought that it was natural for heavy things to ____ and for light things to ___.

fall

rise

Aristotle also thought that _____ motion was natural for objects beyond Earth and that the plants and stars moved in perfect circles around _____.

circular

Earth

What force was thought to have caused a horse and cart to experience violent motion?

the pull of a horse

Before the 1500s, the proper state of objects was thought to be one of ____, unless they were being pushed or pulled or were moving toward their natural resting place.

rest

T/F? Early thinkers thought that violent motion was imposed motion.

true

T/F? It was commonly thought by many ancient thinkers that if an object moves "against its nature," then a force of some kind was responsible

true

T/F? Copernicus thought that Earth and other planets move around the sun.

True

T/F? Copernicus thought that Earth was the center of the universe.

False

T/F? Copernicus did not publish his ideas until he was near death.

True

T/F? Copernicus lived a long and happy life after his works were published.

False

Why did Copernicus do most of his work in secret?

His ideas were very controversial, he worked in private to avoid persecution.

What was one of Galileo's great contributions to physics?

demolishing the notion that a force is necessary to keep an object moving.

A force is any ____ or ____.

push

pull

Explain what friction is and how it acts.

Friction is the force that acts between materials that touch as they move past each other. caused by irregularities in surfaces that are touching

Based on his experiments with rolling balls, Galileo was able to conclude that when friction is present, a ____ is needed to keep an object moving

force

Describe the property of inertia.

a body of motion will stay in motion unless acted on by a force & same for a body at rest.

What is another name for Newton's first law of motion?

law of inertia

State Newton's first law of motion

every object continues in a state of rest, or of uniform speed in a straight line, unless acted on by a non zero net force

Use Newton's first law of motion to explain what happens to dished on a table when the tablecloth is quickly pulled from beneath them.

dished on a tabletop= at rest. Remain at rest even when tablecloth is moved because of friction between dished and tablecloth is not significant enough to move the dished

Objects in a state of rest tend to remain at test; only a ___ will change that state.

force

Use Newton's first law of motion to explain why an air hockey puck slides on the game table with no apparent loss in speed. Name two things that can cause the pouch to change its state of motion.

the puck will move indefinitely in a straight line

Cause pouch to change its state of motion: 1. if it is stuck. 2. if it hits the side of the table

Once an object is moving in a force-free environment, for how long will it move in a straight line?

indefinitely

T/F about the mass of an object?

- the amount of inertia an object has depends on its mass

- the more mass an object has, the greater its inertia

- mass is usually measured in kilograms

true

T/F? Mass is a measure of the gravitational force acting on an object.

false

___ is a measure of the amount of material in an object and depends on the number of and kind or atoms that compose it.

Mass

T/F? A stone has the same mass on Earth and on the moon, but its weight is less on the moon.

true

____ is the quantity of matter in an object.

Mass

___ is the force of gravity on an object.

Weight

traditional unit of weight in the U.S

pound

measure of matter in most parts of the world

mass

SI unit of mass

kilogram

SI unit of force

newton

If Earth is rotating at 30 km/s, explain how a bird sitting on a tree can drop down vertically and grab a worm that is crawling on the ground.

The Earth, bird and ground all move at once. Since all move at once, Earth does not affect the bird

What is true about: A girl is sitting on a bus that is traveling at 30 km/h. She is throwing her tennis ball gently into the air and catching it.

-the tennis ball is behaving as if the bus were at rest

-gravity affects only the vertical motion of the tennis ball