Chapter 2 Motion along a line Flashcards
When describing where an object is located at we need to identify the _______ point, the distance, or the direction
Reference point
The reference point is called the _______
Origin
To describe the location of something we give its _________ from the place & the direction
Distance
For graphing motion along a line the line of motion is the ___ axis & the origin is x=0 (or just 0) so the position of an object can be describe by its x-coordinate or how far from the origin point
X-axis
Displacement
Is the change of position (final position- initial position) (symbol i delta X)
Velocity
Is a quantity with magnitude & direction where the magnitude is the speed that the object is moving
Velocity depends on both __________ & the time interval
Displacement
Average Velocity
When a displacement (delta x) occurs over a time interval (delta t) the average velocity during that time interval is delta x divided over delta t
Since delta t is always ________ the direction of the average velocity ( whether its -/+) depends on the __________
Displacement
Average speed is the ______________
Total distance traveled divided by the time interval
Instantaneous velocity
Is a quantity where the magnitude i the speed & the direction is the direction of motion
A ________ shows the position of an object over a period of time so its a graphs that x vs t
Motion diagram
For a graph that deals with displacement (delta X) on the x axis & time (delta T) on the y axis the velocity is the _________
Slope
In a displacement vs t graph the tangent line is the _____________
Instantaneous velocity
For a graph that is velocity vs time the _________ is the area under the graph (or the shape formed) ( the units are usually just meters_
Displacement
When finding the displacement with graphs of changing velocity you would have to make smaller ________ for the certain area under the graph and then add up the area of all the shapes formed to get the total displacement
Shapes
Acceleration
The rate of change of velocity (tells you how the velocity is changing)
Average acceleration
Average acceleration during a time interval is the change velocity divided by the time interval (units is m/s2)
To find ____________ acceleration have to calculate the average acceleration during a very short time interval
Instantaneous
When acceleration & velocity is both in the same direction ( if both are in the positive x-direction or in the negative x-direction) the object is _________
Speeding up
Only when acceleration & velocity are in the ______ direction when the object is slowing down
Opposite
When velocity is positive & acceleration is negative the object is moving in the positive x-direction the object is ________
Slowing down
When velocity is negative & acceleration is positive the object is moving in the positive x-direction the object is ________
Slowing down
In a graph that is acceleration vs velocity the slope of the graph is the acceleration & the area under the graph is the __________
Velocity
What are the 4 kinematic equations used when acceleration is constant?
- delta V= a(delta)T
- delta X = ½(Vf + Vi) (delta)T
- delta X = Vi(delta)T + ½a(delta T)2
- Vf2 - Vi2 = 2a(delta)X
How do you calculate average velocity when acceleration is constant?
V = ½(Vf + Vi)
In free fall its assumed that no other forces act on an object besides __________
Gravity
An object in free fall has a constant downward acceleration called the ___________
Free-fall acceleration (gravity) (g is the symbol) (g=9.80m/s2)
When dealing with vertical motion the y-axis is positive pointing upward & negative when pointing downward so in free fall the acceleration is what?
a = -g (-9.80m/s2)
If an object is moving downward gravity ________ it up & if its moving upwards gravity slows it down
Speeds
Explain why at the object peek height an object velocity is zero but acceleration isn’t zero?
When an object is at its peak height its velocity is zero but acceleration isn’t zero because when an object is thrown upwards its velocity is positive but when its falls back down its velocity is negative so acceleration can’t be zero because its needed to change the velocity
When there no acceleration (when it says something travels at constant speed or constant velocity) what equation do you use?
delta X = vt (velocity x time)
