Chapter 3: Laws Of Motion Flashcards
(26 cards)
What does geocentric mean?
Imagining that earth is the center of the universe.
WHat does heliocentric mean?
The sun centered theory of the solar system
What is apparent retrograde motion?
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.
what are Kepler’s Laws?
Three empirical rules that accurately describe the motions of the planets.
What does it mean for a law to be empirical?
The law is derived directly from observations or evidence, not logic or theoretical interference.
Force
Push or a pull on an object.
Inertia
The tendency of an object to maintain its state- either motion or rest- until it’s pushed or pulled by a net force.
Newton’s first law of motion
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
Frame of reference
The place from where you observe positions and motions.
Inertial frame of reference
A frame of reference that is not accelerating. ie, a glass of water in a moving car.
Acceleration
Any change in motion.
The rate at which velocity changes
Newton’s third law of motion
For every force, there is an equal and opposite reaction force.
Velocity
a quantity that describes both the speed of an object and the direction it’s moving
Newton’s second law of motion
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)
Gravity
A natural phenomenon by which all things with mass are attracted toward one another
What is the equation for newton’s universal law of gravity?
Fofgravity = G (M)(M) / R^2
M= mass of an object
R= distance between the two objects
G= Really small number (7x10^-11)
What is gravitational force?
Force due to the gravitational interaction between two or more objects with mass
Why is the gravitational acceleration identical for all objects?
I.e: doubling the mass of an object doubles the gravitational force acting on it.
What is the inverse square law?
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.
What is the universal gravitational constant?
- 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
Newton’s universal law of gravitation states that gravitational forces have three properties:
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.
Why do astronauts float in space?
They are constantly falling as the space craft is pulled by earth’s gravity into an orbit.
What is centripetal force?
a force that acts on a body moving in a circular path and is directed toward the center around which the body is moving.
What is uniform circular motion?
Motion in a circular path at a constant speed.
-moons and satellites travel in an orbit, or a uniform circular motion
