Kinematics Terminology Scalar vs Vector Scalar quantities that have only a size but no direction i e distance speed Vector quantities that have a size and direction ie displacement velocity ID: 486860
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Slide1
1.1 Motion and Motion GraphsSlide2
Kinematics Terminology
Scalar vs. Vector
Scalar:
quantities that have only a size, but no direction
i
e
:
distance, speed
Vector:
quantities that have a size and direction
ie
:
displacement, velocitySlide3
Kinematics Terminology
Distance (
d
)
– the length of the path travelled Position ( d ) – describes the distance and direction from a reference pointDisplacement ( Δd ) – the change in position of an objectSlide4
Speed and Velocity
Average Speed
– the total change in distance over an elapsed period of time
(m/s)
Average Velocity
– the change in displacement over an elapsed period of timeSlide5
Speed and Velocity
Instantaneous Velocity
– the velocity of an object at a specific timeSlide6
Example
A jogger takes 25.1 s to run a total distance of 165 m by running
140
m [E] and then 25 m [W]. The displacement is 115 m [E]
.
(a) Calculate the jogger’s average velocity. (b) Calculate the jogger’s average speed.Slide7
Position-Time Graphs
A straight line represents uniform motion
Positive slope
forward motion
Negative slope backward motionZero slope stationarySlide8
A curved line represents non-uniform motion (acceleration)
v
avg
slope between two pointsvist slope of tangent
Position-Time GraphsSlide9
Example
The position–time graph
shows
the details of how an
object moved.
Calculate the average velocity during thetime interval t=1.0 s to t=2.5 s.Slide10
Acceleration
Uniform Motion
– motion at a constant speed in a straight line
Non-uniform Motion
– the change in an object’s velocity
Acceleration – the change in velocity over an elapsed time periodSlide11
Velocity-Time Graphs
A straight line represents constant acceleration
Positive slope
acceleration
Negative slope deceleration
Zero slope constant velocity (no acceleration)Slide12
Velocity-Time Graphs
A curved line represents non-uniform acceleration
a
ave
slope between 2 pointsainst slope of tangentSlide13
Homework
Read
Section 1.1
Questions
p. 10 #1-3
p. 15 #1-3 p. 16 #1-2, 4-6