Constant motion Flashcards
Position
The location of an object in relation to some “reference point”
Reference Point
A point or exact location that can be used to help describe the location of some other point or object.
If you say a ball is 30 feet up, what would typically be your reference point.
The ground below the ball.
(The ball would be 30 feet away from the reference point or ground in this case)
Speed
How fast an object is traveling. Distance the object travels in a unit of time.
(Direction is not important)
The location of an object in relation to some “reference point”
Position
A point or exact location that can be used to help describe the location of some other point or object.
Reference Point
How fast an object is traveling.
(Direction is not important)
Speed
Velocity
The speed and direction an object is travelling.
Vector
A quantity that has both magnitude and direction.
Example:
Forces are vectors because if you push or pull on something, there is a magnitude (size) of your push, and there is always a direction of your push.
Magnitude
How big something is.
Scaler
A quantity that has a magnitude (size) but no direction.
Examples:
Temperature. 78 degrees tells you how “big” the temperature is, but there is no direction to 78 degrees.
Is “speed” a scaler or a vector?
It is a scaler. Speed has a magnitude (size) but no direction.
Example: 50 mph.
Is velocity a vector or a scaler?
Velocity is a vector.
It has both magnitude (size) AND direction.
Example:
Her velocity was 30 mph north.
A quantity that has both magnitude and direction is called a _______________.
Example:
Forces are ________ because if you push or pull on something, there is a magnitude (size) of your push, and there is always a direction of your push.
Vector
How big something is.
Magnitude
A quantity that has a magnitude (size) but no direction.
Examples:
Temperature. 78 degrees tells you how “big” the temperature is, but there is no direction to 78 degrees.
Scaler
Reference object
An object that can be used as a reference for both position and for velocity.
In order to describe the position of an object, you must always refer to a ___________ _____________.
Reference Point
(or reference object)
In order to describe the velocity of an object, you must always refer to a ___________ _____________.
reference object
When you describe the velocity of a car, your typical reference object would be what?
The surface of the road beneath the car.
Linear Motion
Motion along a line
In motion along a line, what is the difference between the following two “velocities?”
17 m/s
-17 m/s
The objects are traveling at the same speed, but in opposite directions.
In linear motion, we can use plus and minus to represent different directions.
In linear motion, how will we show the direction an object is travelling?
With a “+” sign or a “-“ sign.
The plus would mean one direction, and the minus would mean in the exact opposite direction.
Position/Time graph
A motion graph with “time” on the horizontal axis and “position” on the vertical axis.
This graph shows the motion of 4 objects.
Which object is not moving?
C
(did you remember to look at the axes?)
Which object is moving the fastest?
A
The steepest line on a position/time graph represent the fastest moving object.
(A is moving the opposite direction from B and D)
Velocity/Time graph
A motion graph with time on the horizontal axis and velocity on the vertical axis.
Look carefully at the following graph. Does this show and object that is moving or standing still.
What is meant by the acronym:
A.U.T.O.graph
When we look at graphs, we will always think about:
A - the axes
U - the units
T - the trace
O - the origin
When we refer to the “trace” on a graph, we are talking about …
The best fit line or curve on the graph.
v
the symbol for velocity
d
the symbol for distance
P
the symbol for position
(X marks the spot)
t
The symbol for time
Subscript
A letter written smaller and below the rest of the writing.
<span>v</span>t
Here the “ t “ is subscripted
the symbol for velocity
v
the symbol for distance
d
the symbol for position
P
The symbol for time
t
A letter written smaller and below the rest of the writing.
<span>v</span>t
Here the “ t “ is subscripted
Subscript
Kinematics
The study of motion
Constant Speed
Not speeding up or slowing down
The study of motion
Kinematics
Instantaneous Speed
How fast an object is going at an instant in time. It is what is shown on the speedometer of a car.
Average Speed
A single speed that can be used to represent an object’s speed during a period of time, even if the object is changing speeds.
Slope
The angle of a line on a graph
How fast an object is going at an instant in time. It is what is shown on the speedometer of a car.
Instantaneous Speed
A single speed that can be used to represent an object’s speed during a period of time, even if the object is changing speeds.
Average Speed
This is called a
Motion Map
The angle of a line on a graph
Slope
The formula for calculating the slope of a line.
Slope = rise/run
Slope = rise/run
The formula for calculating the slope of a line.
Displacement
How far you are from where you started, and in what direction.
Distance
How far you have travelled.
What is the formula for finding
Average Speed
What quantity is this device used to measure?
Time
What quantity is this device used to measure?
Volume
What quantity is this device used to measure?
Length
What quantity is this device used to measure?
Mass
(Note, mass is different than weight)
Scales measure weight
Balances measure mass
True or false.
This object is moving at a constant speed.
False
( I guess zero is a constant speed, but it is not really moving, is it. It just stays at a position of 8 meters from the reference point)
In linear motion, the difference between
-55 mph
and
+55 mph
is?
Direction only
In linear motion, the “+” and the “-“ symbols are used to show what?
Direction
Which object is moving faster?
A car going +10 mph
A moped going - 10 mph
Neither.
They are both going the same speed, but in different directions.
You walk all the way around a typical high school track. Its about 400 meters.
Your Distance = ___________
Your Displacement = _____________
Your Distance = ___\_400-m______\_
Your Displacement = ___\__0-m\________
Distance is how far you travel.
Displacement is how far you end up from the starting point.
You are about to go outside to take measurements necessary to calculate your top running speed. What measurements would you need to take.
Distance
and
Time
(because S = d/t )
When we make a motion graph, what variable will ALWAYS be on the horizontal axis?
Time
(Even if time is the dependent variable, we will always put it on the horizontal axis in motion graphs.)
Is displacement a vector or a scalar?
Displacement is a vector. It has both magnitude and a direction.
Is the following a description of a distance or a displacement?
He travelled 20 miles North.
Displacement
(Magnitude = 20 miles)
(Direction = North)
Is the following a description of a distance or a displacement?
He traveled 30 meters.
Distance
It has no direction, so it cannot be a displacement.
30 meters is a distance, so its a scalar quantity.
If you add a direction so it reads
30 meters north, then it becomes
_______________ which is a ______________
If you add a direction so it reads
30 meters north, then it becomes
displacement which is a vector.
Time
Vector Quantity or not?
Not
3 seconds does not have a direction.
No direction, not a vector.
Distance
Vector Quantity or not?
Not
25 meters does not have a direction.
No direction, not a vector.
Temperature
Vector Quantity or not?
Not
37 degrees does not have a direction.
No direction, not a vector.
Speed
Vector Quantity or not?
Not
50 mph does not have a direction.
No direction, not a vector.
Velocity
Vector Quantity or not?
Vector Quantity
50 mph - North has both magnitude (50) and direction (North).
So, its a vector or vector quantity.
The definition of “Displacement” is “how far you are from the reference point and in what direction.”
Displacement can also often be thought of as:
How far you are from where you started. (and in what direction)
“Uniform Linear Motion”
is just a physicsy way of saying….
“Moving in a straight line at a steady speed.”
Object “A” has a velocity of -5m/s.
Object “B” has a velocity of -3m/s.
Object “C” has a velocity of 0 m/s.
Which object is moving the fastest?
Object A is moving the fastest.
(Both objects are moving in the negative direction. Object “A” is moving at 5m/s, object “B” is only moving at 3m/s. Object “C” isn’t even moving, so it is pretty much going the slowest.)
Which of the following velocities represents the object travelling most slowly.
Car 1 is traveling at -40 mph
Car 2 is traveling at 0 mph
Car 3 is traveling at +20 mph.
Car 2 is traveling most slowly. (It is not even moving)
(Car “1” is traveling the fastest, even if it is moving in the negative direction)
