physics
a branch of science that involves the study of the of the physical world: energy, matter, and how they are related
dimensional analysis
the methos of treating units as algebraic quantities, which can be cancelled
significant digits
valid digits for measurement
model
a representation of an idea, event, structure, or object to help people better understand it
scientific method
making observations, doing experiments, and creating models or theories to support your results
hypothesis
an educated guess about how variables are related
scientific law
a rule of nature that sums up related observations to describe a pattern in nature
scientific theory
an explanation based on many observations supported by experimental results
measurement
a comparison between an unknown quantity and a standard
precision
the degree of exactness of a measurement
accuracy
how well the results of a measurement agree with the "real" value
independent variable
the factor that is changed or manipulated during an experiment
dependent variable
the factor that depends on the independent variable
line of best fit
a line drawn as close to all points as possible to better model the data
linear relationship
y=mx+b
quadratic relationship
y=ax^2+bx+c
inverse relationship
y=a/x
instantaneous velocity
the speed and direction of an object at a particular instant
magnitude
the size of a quantity
position
the location of an object relative to an origin
time interval
the formula t(f)-t(i) represents this
vector
a quantity with both magnitude and direction
average velocity
ratio of the change in position to the time interval during which the change occurred
coordinate system
a system that defines the zero point of the variable you are studying
origin
the zero point is also called the
position-time graph
a graph with time data on the horizontal axis and position data on the vertical axis
motion diagram
this shows a series of images showing the position of a moving object over equal time intervals
resultant
a vector that represents the sum of two or more vectors
particle model
a simplified motion diagram that shows the object in motion as a series of points
distance
a scalar quantity that is the length, or size, of the displacement vector
scalar
a quantity that has only magnitude
instantaneous position
the location of an object at a particular instant
displacement
the vector quantity that defines the distance and direction between two positions
average speed
the absolute value of the slope on a position-time graph
acceleration
the rate at which the velocity of an object changes
velocity-time graph
a graph that can be used to plot the velocity of an object versus time and to determine the sign of an objects acceleration
average acceleration
the change in an object's velocity during a measurable time interval, divided by that specific time interval; is measured in m/s^2
instantaneous acceleration
the change in an object's velocity at a specific instant of time
free fall
the motion of a body when air resistance is negligible and the motion can be considered due to the force of gravity alone
free-fall acceleration
the acceleration of an object due only to the effect of gravity
force
A push or pull exerted on an object that causes a change in motion; has both direction and magnitude and may be a contact or a field force
system
object or objects of interest that can interact with each other and the external world
free-body diagram
A physical model that represents the forces acting on a system
net force
the vector sum of all the forces on an object
Newton's second law
States that the acceleration of an object is proportional to the net force and inversely proportional to the mass of the object being accelerated
Newton's first law
States that an object at rest will remain at rest, and a moving object will continue moving in a straight line with constant speed, if and only if the net force acting on that object is zero
inertia
The tendency of an object to resist change
equilibrium
The condition in which the net force on an object is zero
weight
the gravitational force experienced by an object
gravitational field
the vector quantity that relates the mass of an object to the gravitational force it experiences at a given location; represented by the symbol g
apparent weight
The force experienced by an object, resulting from all the forces acting on it, giving the object an acceleration
weightlessness
An object's apparent weight of zero that results when there are no contact forces pushing up on the object
drag force
The force exerted by a fluid on an object moving through the fluid; depends on the object's motion and properties and the fluid's properties
terminal velocity
The constant velocity of an object that is reached when the drag force equals the force of gravity
interaction pair
A pair of forces that are equal in strength, but opposite in direction
Newton's third law
States that all forces come in pairs and that the two forces in a pair act on different objects and are equal in strength and opposite in direction
tension
The specific name for the force exerted by a rope or a string
normal force
The perpendicular contact force exerted by a surface on another object
components
projections of a vector parallel to the x-axis and another parallel to the y-axis
vector resolution
the process of breaking down a vector
kinetic friction
the foce exerted on one surface by a second surface when the two surfaces rub against each other because one or both od the surfaces are moving
static friction
the force exerted on one surface by a second surface when there is no motion between the two surfaces
coefficient of kinetic friction
the slope of a line on a kinetic friction force v. normal force graph. relates frictional force to normal force and depends on the two surfaces in contact. it is needed to calculate kinetic friction
coefficient of static friction
a dimensionless constant depending on the two surfaces in contact. it is used to calculate the maximum static friction that needs to be overcome before motion begins. It is larger than the coefficient of kinetic friction
equilibrant
a force that places an object in equilibrium; the same magnitude as the resultant but opposite direction