Ch.01-4 Flashcards
What are the requirements to state position?
we must specify an origin, a length, and a direction
what is the length, direction, and origin of this statement
I am 18 miles north of my home
18 miles is the length
North is the direction
The origin is my home
what are the components of a vector
a vector has a magnitude (size) and direction
what is displacement
displace is the difference or change in position (xf-xi)
does the origin matter in displacement?
no, the displacement is independent of the origin
what type of quantity is a displacement
it is a vector quantity, it includes direction
what type of quantity is distance
it is a scalar quantity, it does not include direction
what is a scalar quantity
they are quantities described with a single unit and only have magnitude (no direction)
what is a vector quantity
vectors have magnitude and direction
displacement, acceleration, velocity, etc
what does the length of an arrow represent with vectors?
its magnitude
what type of quanitity is magnitude
it is a scalar, the size itself cannot be negative but it can be pointing in a negative direction relative to origin
what is 1-D motion
motion constricted to one axis, it can have a + or - sign relative to the origin
how do you read a motion diagram?
the dots are taken at equal time intervals (even if the position is different, they are all captured at the same time interval between each)
dots that are equally spaced are moving at a constant speed
dots that get closer together indicate a slower speed
dots that are further apart indicate a faster speed
how do you read a position vs time graph
the slope (∆x/∆t) is the velocity
steeper slopes indicate faster velocities
how do you read the velocity in a position vs time graph
the absolute value of the slope is the speed
the sign is the direction
how do you read a velocity vs time graph
if the slope was negative, the line would be below the t axis
the higher the magnitude, the higher the line
what indicates a constant velocity in a velocity vs time graph
if the line is flat
what indicates an acceleration in a velocity vs time graph
the acceleration is the slope, if the line is not flat, there is a change in the velocity
what is acceleration
it is the change in velocity over a time interval
what is uniform motion and what is it indicated by in a motion diagram
it is movement with a constant velocity, it is indicated by equally spaced dots
what does the velocity in uniform motion tell us?
it tells us the amount by which the position changes every second
what equations can we use when we are dealing with uniform motion?
we can use
xf=xi+v∆t to find the final position
we can use
∆x=v∆t to find the displacement
in a velocity vs time graph, what does the area under the graph tell us?
it tells us the displacement
what is instantaneous velocity?
it is the velocity at an instant, the slope of the tangent line
what is acceleration
it is the change of velocity in a time interval, it is the slope in the velocity vs time graph
what is freefall
it is motion where only gravity affects the motion
what is the standard acceleration in freefall?
9.80m/s^2
when an object is falling in freefall, what is the magnitude of its acceleration? What do we say is the acceleration?
the magnitude is 9.80m/s^2, its acceleration is -9.80m/s^2 because it is falling in a negative direction
when is an object in uniform motion?
if and only if the line in its position vs time graph is straight
for an object speeding up, which way does the acceleration point?
it points in the same direction as the velocity
for an object slowing down, which way does the acceleration point?
it points in the opposite direction of the velocity
