Chapter 3 Physics Test

Law of Inertia

A body at rest stays at rest; a body in motion stays in motion in a straight line unless acted upon by a NET FORCE. "Every object continues in a state of rest, or of motion in a straight line at constant speed, unless it is compelled to change that state by forces exerted upon it."

0 N

A hockey puck is set in motion across a frozen pond. If friction and air resistance are ignored, how much force is required to keep the puck sliding at constant velocity?

About 30 m/s.

A package falls off a truck that is moving horizontally at 30 m/s. Neglecting air resistance, which of the following best approximates the horizontal speed of the package just before it hits the ground?

The milk carton has inertia.

A sheet of paper can be withdrawn from under a container of milk without toppling it if the paper is jerked quickly. Which of the following does this best demonstrate?

Exactly below the midpoint of the ceiling.

A truck is moving at constant velocity. Inside the storage compartment, a rock is dropped from the midpoint of the ceiling and strikes the floor below. Where does the rock hit the floor?

mass

An object maintains its state of motion because it has . . .

The one on the moon.

An object weighs 30 N on Earth. A second object weighs 30 N on the moon. Which has the greater inertia?

Not enough information to say.

An object weighs 30 N on Earth. A second object weighs 30 N on the moon. Which has the greater volume?

Force

Any push or pull that can change the motion of an object.

circular; Earth

Aristotle also thought that ______ motion was natural for objects beyond earth and that the planets and stars moved in perfect circles around _______.

natural motion; violent motion

Aristotle divided motion into type types: ________ and ________.

fall; rise

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

force

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

equilibrium

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.

inertia, mass, and volume.

Compared to a 1-kg block of iron, a 2-kg block of iron has twice as much . . .

mass

Comparing the concepts of mass and weight, one is basic - fundamental - depending only on the internal makeup of an object and the number and kind of atoms that compose it. The concept that is fundamental is _____.

the back of the cart hits the ball

Consider a ball resting in the middle of a cart: if you quickly pull the cart forward:

In the absence of the tension in the string pulling the rock in circular motion, the rock would follow a straight line path, tangent to its' curve at a constant speed.

Consider a rock swinging in a circle at the end of a string: what is the path of the rock when the string breaks (or you let go of the string)?

Galileo

Followed Copernicus and performed this experiment to debunk Aristotle's theory of gravity. Believed that objects fall at speeds proportional to their mass. The 2 objects fall at the same rate proving that acceleration due to gravity is independent of mass.

Friction

Force that acts between materials that touch as they move past each other. Caused by the irregularities in the surfaces of objects that are touching.

We move along the Earth due to inertia.

If Earth moves around the Sun at a speed of about 67,000 mph, why aren't we swept off the fast-moving Earth?

In the absence of the Force of Gravity pulling the planets toward the Sun, the planets would follow a straight line path tangent to their curve at a constant speed.

If the force of gravity between the sun and planets suddenly disappeared, what type of path would the planets follow? Why?

at your feet

If you drop a coin from above your head while standing in the aisle of a moving bus, the falling coin will land:

pound

In the United States, it is common to measure the mass of something by measuring its gravitational pull to Earth, its weight. The common unit of weight in the U.S. is the _______.

If your chunk of gold weighed 1N on the moon.

In which case would you have the largest mass of gold?

mass

It can correctly be said that _______ is a measure of "laziness" of an object.

Violent Motion

Manually imposed motion on an object. It was thought that for an object to continue in motion, a force must be continuously supplied.

NOT equal

Mass and weight are _____ to each other but are proportional to each other in the same location.

Weight

Measure of gravitational force of attraction between two objects. Measured in Newtons (N) or pounds (lbs).

Mass

Measure of inertia; depends on the amount of matter present. Measured in kilograms

straight up; straight down

Natural motion on earth was once thought to be either ______ or ______.

vehicle

Objects in the vehicle are moving with the ______. If the car stops suddenly, the objects continue moving at the speed the car was traveling.

mass

On the moon's surface, where gravity is only about one sixth of Earth gravity _______ of the stone would be the same as on Earth.

Copernicus

Proposed that astrological motion was not "natural" motion. He proposed that the Earth moved around the Sun. Very controversial during the pre-1500's when Earth was thought to be at rest or that its' motion was its' "natural" tendency.

Every object continues in a state of rest or of uniform speed in a straight line unless acted on by a nonzero net force.

State Newton's first law of motion.

Natural Motion

Straight up or straight down. Objects sought their "natural" position.

True

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

False

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

True

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

False

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

True

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

True

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

kilogram; newton

The International System of UNits (SI) unit of mass is the _______ and the SI unit of the force is the ______.

Volume

The amount of space an object takes up.

weight

The concept that additionally depends on location in a gravitation field is ______.

Tangent to the curve and straight until opposing force.

The force of gravity holds the planets in orbit around the sun; if that force suddenly disappeared, in what kind of path would the planets move?

The horse pulling.

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

Demolished the notion that a force was necessary to keep an object moving.

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

1kg X 9.8 m/s2 = 9.8 Newtons

When 1 kg is accelerated at 9.8 m/s2, what is the resulting force?

Car battery.

Which has the greater mass? A car battery or a king sized pillow?

The gravitational attraction between you and Earth.

Which of the following best describes your weight?

directly proportional; twice

While mass and weight are not the same, they are ______ to each other. In the same location, twice the mass has ______ the weight.

To follow a straight-line path

Whirl a rock at the end of a string and it follows a circular path. What is the tendency of the rock if the string were to break?

To escape prosecution.

Why did Copernicus do most of his work in secret?

Weight

______ depends on an object's location, whereas mass does not.

Mass

______ is a measure of the amount of matter in an object and only depends on the number and kind of atoms that compose it.