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Ch 11
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Gravity
Terms in this set (70)
Motion
An objects change in position relative to a reference point
Frame of reference
A system for specifying the precise location of objects in a space and time
Motion
When an object changes position with respect to a frame of reference the object is in __________
Reference Direction, north south east west up or down
You can describe the direction of an objects motion with a _______ _________- ________,__________,_______,_______,_________, or _______
How far an object moves
In addition to knowing direction you need to know ________________ to directly describe its motion.
Distance
To measure ___________ you measure the length of the path the object took
Displacement
the change in position of an object
Speed
What is the distance traveled divided by the time interval during which the motion occured
Velocity
the speed of an object in a particular direction
Speed
Tells how fast an object moves
Velocity
Tells both speed and direction that an object moves
North south east or west of a fixed point and an angle from a fixed line
What two ways can direction of motion be described
positive velocity
If a body is moving in one direction it has __________
Negative velocity
If a body is moving in the opposite direction it has ___________
Up and right
What are some examples of negative velocity
Down and left
What are some examples of negative velocity
Resultant velocity
Combined velocities determine ________
Distance traveled and the time it took to travel that distance
To calculate average speed you must measure what 2 things
M/S
What is the SI unit for speed
Time interval accurate
The shorter the __________ the more _______ the measure of speed will be
Speed x time
What is the formula for distance
distance divided by time
What is the formula for speed
distance divided by speed
What is the formula for time
Distance and time
You can also plot a graph showing the ______ on the verticle axis and the _______ on the horizontal axis
Motion
_______ can also be studied using a distance vs time graph
Independent variable and dependent variable
As a rule the x axis on a bar graph represents the ________ and the y axis represents the __________
Slop
The _________ of distance vs time graph equals speed
Vertical change divided by horizontal change
What is the formula for slop
Velocity
WhAt has speed and direction
Accleration
When an object undergoes _________________ its velocity changes
Acceleration
The rate at which velocity changes overtime
Speed, direction, or both changes
How can you tell if an object accelerates
Speeding up or slowing down
Because acceleration takes into account changes of speed and or direction you can accelerate while never _______________ or _________
You need to measure the objects velocity at different times
How do you calculate the acceleration of an object moving in a straight line?
Dividing the change in the objects velocity by the time over which the change occurs
How can the average acceleration over a given time interval be calculated
Acceleration= final velocity - initial velocity/ time
What is the acceleration formula
Gradualing changing, rapidly increasing
If acceleration is small the velocity Is ______________. If the acceleration is large the velocity is ______________.
That and objects velocity is increasing
For a straight line motion a positive acceleration means what
The objects velocity is decreasing
For a straight line motion negative acceleration means what
Speed vs time graph
How can you find acceleration on a graph
Speed time
For an acceleration graph _______is plotted on the y axis and ________is plotted on the x axis
Force
What is an action exerted on a body in order to change the body's state of rest or motion.
Magnitude and direction
Force has _________&___________
Gravity electromagnetic force strong nuclear work weak nuclear work
What are the four fundamental forces in nature
Gravity
Force we feel everyday
Electromagnetic force
Friction is a result of the force
Strong and weak nuclear force
Both act over a short distance; don't experience directly in everyday life
Strength and distance
These forces vary in __________&__________
Strong nuclear force
This force holds together the particles in the nucleus of an atom and is the strongest force
Gravitational and electromagnetic force
What two forces act over long distances
1/100 electromagnetic force
The electromagnetic force is _______ of the strength of the strong force and the gravitational force is far weaker than the _____________
Forces
_________can act through contact or at a distance
Pushes/pulls
What are some contact forces
Field forces
__________ don't require that objects touch each other
Gravity and magnetism
What are some examples of field forces
Move or stop
Both types of forces can cause an object to __________ or ___________
Net force
Whenever there is a __________ acting on the object, the object accelerates in the direction of it.
Balanced
When the forces applied to an object produce a net force of zero the forces are _______________
balanced forces
____________ don't cause an object at rest to start nor do they cause a change in the motion of a moving object
Like a single force, combines the direction
If forces act in different directions that are not opposite to each other the combination of forces act __________________ and causes acceleration in a direction that __________________ of the applied forces
Friction
Is a force that opposes motion between two forces that are in contact
static and kinetic
What are the two types of friction
Static friction
The force that resists the initiation of sliding motion between two surfaces that are in contact and are at rest
kinetic friction
The force that opposes the movement of two surfaces that are in contact and are moving over each other
Sliding and rolling friction
What are the two types of friction
Sliding friction
When two objects slide past each other
Rolling friction
When a rounded object rolls over a flat surface
Friction
_________ is necessary for everyday tasks
Lowered
Unwanted friction can be ________
Increased
Helpful friction can be increased
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