Vectors and Scalars, Motion in one direction. Flashcards
What is the definition of a Scalar quantity?
Physical quantity that has magnitude. (size)
What is the definition of a Vector quantity?
Physical quantity with both magnitude and direction.
How do we indicate a Vector quantity?
With an arrow above the letter. Or in bold.
What do we need to draw a Vector?
Scale. Arrow the correct length. Direction labelled positive or negative, North or 360 degrees. Arrow head. Write the magnitude of the vector.
What is the final Vector called when adding or subtracting Vectors?
The resultant vector. From the tail of the first vector to the head of the second vector.
Which graphical representation of the below vectors has the greater magnitude?
A ——)
B ————)
What is the difference between the below vectors?
A (——–
B ——–)
B, because the arrow is longer. But both A and B are pointing in the same direction.
Both A and B have the same magnitude but are pointing in different directions.
Fill in the missing words:
The direction of a vector must be made with respect to a particular —————- —- ————. This is the point of view from which a system is observed.
Frame of reference.
Term for this definition:
When two vectors have equal magnitude and direction.
Vector Equality.
What are the three features of motion that we use to describe how an object moves.
Position/Displacement: Tells us about the objects location or change thereof.
Speed/Velocity: Tells us how fast the object is moving and for velocity where to.
Acceleration: Tells us how fast the objects speed and velocity is changing.
What occurs when an object changes it’s position?
Motion.
Term for this definition:
The measurement of location of an object defined relative to a reference point.
Position.
What is the definition of distance?
Is it a Vector or Scalar?
The actual path length that an object has moved from it’s initial position to it’s final position.
Scalar.
What is the definition of displacement?
Is it a Vector or Scalar?
The change in an objects position.
Vector.
What are the three differences between Distance and Displacement?
Distance: Displacement
> Path dependent < Path independent
> Scalar < Vector
> Always positive < Can be positive or
negative.
What is the definition of speed?
What is the definition of velocity?
S: The rate of change of path length with respect to time.
V: The rate of change of position with respect to time.
Equations for Savg and Vavg?
Unit for both: m.s^-1
S(average) [SCALAR]
= distance travelled over time taken. or
= change in path length over time taken
V(average) [VECTOR]
= change in position over time taken
or
= displacement over time taken
How fast an object is moving at a particular moment.
Instantaneous speed /
Instantaneous velocity
When ———– changes Acceleration exists.
Velocity
T/F
Acceleration is a vector.
There’s no acceleration if constant speed around a corner.
True
False, there is. Because acceleration is a vector. ( Magnitude and direction) The direction changes so there is acceleration.
Is there acceleration when?
a) Constant speed in a straight line.
b) Constant speed and turns a corner.
c) Braking before a stop street.
a) No
b) Yes, change of direction
c) Yes, magnitude changes
What are the three types of motion?
Stationery objects.
Uniform/Constant motion.
Motion at a constant acceleration.
What are the three graphs to graphically represent motion.
Position vs time.
Velocity vs time.
Acceleration vs time.
To go from Acceleration vs time to Velocity vs time. By?
Multiplying a x delta t.
What are the labels for this symbol? -)x A-)x -)Vi -)Vf -)Vavg -)a t At
Position Displacement Initial Velocity Final Velocity Average Velocity Acceleration time time interval
What is the equation for? Displacement Average speed Average velocity Average acceleration
A-)x =Xf-Xi
avgs = d/At
-)Vavg = A-)x / At
-)aavg = A-)V / At
What are these equations? -)Vf = -)Vi + [ -)a x At ] A-)x = [ V-)i + V-)f / 2 ] x At A-)x = V-)i x At + 1/2-)a x At^2 V-)f^2 = V-)i^2 + 2-)a x Ax
Equations of Motion
In graphs of motion:
For stationary objects, motion at constant velocity and uniform acceleration;
What are the trends?
Stationary: Velocity and Acceleration vs time will always be 0. Position vs time a straight line.
Constant motion: Acceleration vs time will always be zero. Velocity vs time a straight line. Position vs time diagonal straight line.
Uniform acceleration: Acceleration vs time straight line. Velocity vs time diagonal straight line. Position vs time curved diagonal line.
