Chapter 3: Laws Of Motion

Question 1

What does geocentric mean?

Answer 1

Imagining that earth is the center of the universe.

Question 2

WHat does heliocentric mean?

Answer 2

The sun centered theory of the solar system

Question 3

What is apparent retrograde motion?

Answer 3

When the planets appear to turn around, move west for a while, then return to moving east.
Happens when planets traveling at different speeds pass each other in their orbits.

Question 4

what are Kepler’s Laws?

Answer 4

Three empirical rules that accurately describe the motions of the planets.

Question 5

What does it mean for a law to be empirical?

Answer 5

The law is derived directly from observations or evidence, not logic or theoretical interference.

Question 6

Force

Answer 6

Push or a pull on an object.

Question 7

Inertia

Answer 7

The tendency of an object to maintain its state- either motion or rest- until it’s pushed or pulled by a net force.

Question 8

Newton’s first law of motion

Answer 8

An object in motion/rest tends to stay in motion/rest in the same direction until a net force acts upon it

An object’s velocity does not change unless acted upon by a net force

Question 9

Frame of reference

Answer 9

The place from where you observe positions and motions.

Question 10

Inertial frame of reference

Answer 10

A frame of reference that is not accelerating. ie, a glass of water in a moving car.

Question 11

Acceleration

Answer 11

Any change in motion.
The rate at which velocity changes

Question 12

Newton’s third law of motion

Answer 12

For every force, there is an equal and opposite reaction force.

Question 13

Velocity

Answer 13

a quantity that describes both the speed of an object and the direction it’s moving

Question 14

Newton’s second law of motion

Answer 14

The change of motion (acceleration) of a body is proportional to the direction of the net force acting on it
(Net force=mass x acceleration) (F=MxA)

Question 15

Gravity

Answer 15

A natural phenomenon by which all things with mass are attracted toward one another

Question 16

What is the equation for newton’s universal law of gravity?

Answer 16

Fofgravity = G (M)(M) / R^2

M= mass of an object
R= distance between the two objects
G= Really small number (7x10^-11)

Question 17

What is gravitational force?

Answer 17

Force due to the gravitational interaction between two or more objects with mass

Question 18

Why is the gravitational acceleration identical for all objects?

Answer 18

I.e: doubling the mass of an object doubles the gravitational force acting on it.

Question 19

What is the inverse square law?

Answer 19

The rule that the effect of a body’s gravity diminishes with the square of the distance from the source.
Aka the sun’s influence on orbiting planets decreases the farther away the planets are from the sun.

Question 20

What is the universal gravitational constant?

Answer 20

• g in equations

-Determines the strength of gravity between two objects. It is the same for all pairs of objects.

-The constant of proportions in the universal law of gravity

6.673 x 10^-11 for earth

Question 21

Newton’s universal law of gravitation states that gravitational forces have three properties:

Answer 21

1.it’s an attractive force that can be drawn along a straight line between the two objects
2. it’s proportional to the mass of one object multiplied by the mass of the other object.
3. it’s effected by distance; the farther away the objects are, the less the gravitational force effects them.

Question 22

Why do astronauts float in space?

Answer 22

They are constantly falling as the space craft is pulled by earth’s gravity into an orbit.

Question 23

What is centripetal force?

Answer 23

a force that acts on a body moving in a circular path and is directed toward the center around which the body is moving.

Question 24

What is uniform circular motion?

Answer 24

Motion in a circular path at a constant speed.
-moons and satellites travel in an orbit, or a uniform circular motion

Question 25

What is circular velocity?

Answer 25

The speed a satellite must be traveling in order to stay on a circular path (orbit)

Question 26

What is the escape velocity?

Answer 26

The minimum velocity at which a satellite must be traveling to escape a planet’s gravitational grasp. When the gravity is escaped, the satellite enters an “unbound orbit.”