chapter 3 Flashcards
position
the distance and direction of an object from the origin
displacement
the change in position of a vector
Instantaneous velocity
a vector quantity whose magnitude is the speed and its direction is the direction of motion
- velocity of an object in a very short period of time
average velocity
when displacement occurs during a time interval
motion diagrams
shows the position of an object at equally spaced times.
- easier to draw it as a series of dots
acceleration
rate of change of velocity
what is the average velocity for a position vs time graph?
the slope of the chord connecting two points
how to interpret a position vs velocity graph
- horizontal portion indicates that the object is at rest
- steeping portions of the graph indicate that the object is moving
- the steeper the graph, the larger the speed of the train
- the sign of the slope indicates direction of motion
- a positive slope indicates a positive direction of motion
how to find the instantaneous velocity on a position vs time graph
make the time of the slope shorter, chord should be between closer points
how to find the displacement of a position vs time graph at constant velocity?
the displacement is the area below the graph
how to find the displacement of a position vs time graph at a changing velocity?
the displacement is calculated using the area below the graph
- small time intervals are used and the areas are added up
- for better precision, the time intervals should be close to zero
newtons second law
- the rate of change of the velocity is proportional to the net force and inversely proportional to the mass of the object
how is instantaneous velocity calculated?
the average velocity over a short period of time
define mass in terms of newtons second law
a measure of an objects inertia+
relative velocity
the velocity of object A relative to object BB is the vector difference of the two velocities as measured in a common reference frame
- we sometimes need to change the order of the subscripts
