# Shared Flashcard Set

## Details

Chapter 2
Motion in One Dimension
26
Physics
09/06/2011

Term
 what is dynamics
Definition
 the study of motion and physical concepts such as force and mass
Term
 what is kinematics
Definition
 this is the part of dynamics that describes motion without regard to its cause
Term
 what is the geocentric model
Definition
 this theory regarded Earth as the center of the universe
Term
 what is the heliocentric model
Definition
 this theory states that Earth and other planets revolve in circular orbits around the sun
Term
 what is a frame of reference
Definition
 this is a choice of coordinate axes that defines the starting point for measuring any quanity, an essential first step in solving any problem in mechanics
Term
 what is displacement
Definition
 this is defined as its change in position and given by: delta x
Term
 what is a vector and give three examples of vector quantities
Definition
 a vector quantity is characterized by having both direction and magnitude.  three examples of vector quantities are displacement, velocity, & acceleration
Term
 what is average speed and how do you find it
Definition
 is the length of the path it travels divided by the total elapsed time
Term
 what is average velocity and how do you find it
Definition
 it is a vector quantity, having both magnitude and a direction. to find average velocity, take the change in displacement and divide it by the change in time
Term
 what ia a position vs. time graph
Definition
 this a graphical interpretation of velocity
Term
 how can you determine the average velocity of a position vs. time graph when the slope is not linear
Definition
 the average velocity of an object during the interval delta t, is equal to the slope of the straight line joining the inital and final points on a graph of the objects position vs. time.
Term
 what is instantaneous velocity
Definition
 this is the speed of your car and the direction it was going at a particular instant in time
Term
 how can you find the instantaneous velocity at any time
Definition
 take the slope of the line tangent to the position vs. time curve
Term
 how is instantaneous velocity different than instantaneous speed
Definition
 instantaneous speed doesnt carry an algebraic sign, for example: +/- 15 m/s is an instantaneous velocity, whereas, 15 m/s is an instantaneous speed   in other words, instantaneous speed is scalar
Term
 what is acceleration
Definition
 this is the change of an object's velocity with regards to time
Term
 when an objects velocity and acceleration are in the same direction, what happens to speed
Definition
 speed increases over time
Term
 when an objects velocity and direction move in opposite directions, what happens to speed
Definition
 speed decreases over time
Term
 what is instantaneous acceleration
Definition
 this is the limit of the average acceleration as the time interval goes to zero
Term
 what can you find from a velocity vs. time graph
Definition
 one can find the average acceleration by taking the delta v divided by the delta t
Term
 how can you find the instantaneous acceleration on a velocity vs. time graph
Definition
 take the slope of the tangent to the velocity vs. time graph at that time
Term
 what is a motion diagram
Definition
 a representation of a moving object at successive time intervals, with velocity and acceleration vectors sketched at each position
Term
 when an object moves with constant acceleration, the instantaneous acceleration at any point in a time interval is
Definition
 equal to the value of the average acceleration over the entire time interval
Term
 what does the area under a velocity vs. time graph always equal
Definition
 it always equals the displacement of the object
Term
 what is a free falling object
Definition
 any object moving freely under the influence of gravity alone, regardless of its initial motion
Term
 how do we denote the magnitude of free falling acceleration
Definition
 by the symbol g
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