chapter 6 lesson 5 Flashcards
free fall
when the only force acting on an object is gravity
what causes an object to accelerate
force of gravity
free fall is motion where acceleration…
is caused by gravity
what is in the air
fluid friction
friction acts against gravity reducing..
reducing acceleration to falling objects
when does air friction increase
as an object falls
it will fall at a
constant velocity
what does air friction reduce
accelerated
what motions act independently
horizontal and vertical
satellites
objects that orbit around other objects in space following a curved path around earth
why do satellites travel around earth instead of falling into it
because earth is curved
what causes a satellite to move ahead
inertia
what continuously changes a satellites direction
gravity
why is an object traveling in a circle accelerate
because of constant change in direction
centripetal force
force that causes an object to move in a circular path
where do centripetal forces always point to
the center of earth
acceleration
rate at which velocity changes
what does velocity mean
change in speed and direction
what does acceleration refer to
increasing speed, decreasing speed, or changing direction
what is another name for change in speed
deceleration or negtaive acceleration
you can change direction with out changing…
speed
what does force mean
push or pull
force is described by its strength and…
in which direction it acts
what is measured by the SI unit
newtons
what is net force
the combination of all the forces on an object
what does net force determine
if and how an object will accelerate
what does a nonzero net force cause
a change in objects motion
friction
the force that two objects exert on each other when they rub against each other
what are two factors that affect the force of friction
types of surfaces involved and how hard they’re pushed against each other
what direction does friction act in
opposite
static friction
acts between objects that aren’t moving
sliding friction
when two solid surfaces slide over each other
fluid friction
when an object moves through fluid
rolling friction
when an object rolls across a surface
gravity
a force that pulls objects towards each other
law of universal gravitation
The force of gravity acts between all objects in the universe that have mass
where does gravitational force exist?
Between any two objects in the universe
what are two factors that affect the gravitational attraction between objects
Mass and distance
mass
Measure of the amount of matter in an object
What causes a greater gravitational force?
More mass
what does gravitational force depend on?
Distance between objects centers 
when distance increases
Gravitational force decreases
weight
A measure of the force of gravity on an object
A moving object will continue at a constant velocity until
A force acts to change its speed and direction
Newtons first law of motion
An object at rest will remain at rest, unless acted upon a nonzero net force. An object moving at a constant velocity, will continue moving at a constant velocity, unless acted upon by a nonzero net force.
inertia
All objects resist change of motion
Newton second law of motion
An objects acceleration depends on its mass, and on the net force acting on it
Newton second law of motion shows that force is measured
Kilograms times meters per second to meters per second
newtons third law of motion
If one object exerts a force on another object, then the second object exerts a force of equal strength in the opposite direction of the the first object
What forces are all around you?
Action and reaction forces
momentum
A characteristic of a moving object that is related to the mass and the velocity of the object
momentum of a moving object can be determined by
Multiplying the objects mass by its velocity
how is momentum measured
Kilograms times meters per second
What is momentum described by
Direction and strength
A quantity that was conserved is
The same before and after
law of conservation of momentum
In the absence of outside forces like friction, the total momentum of an object that interact doesn’t change
