UNIT 01 - Motion (kinematics)

EXPECTATIONS -- Before we start this unit you should be able to:

  • determine the appropriate number of significant figures in a mathematical expression
  • demonstrate the ability to accurately measure an angle between vectors using a protractor (either online or a plastic tool in my classroom or at home)
  • demonstrate a mastery of scientific notation (including estimating)
  • demonstrate ability to convert between data types using 'railroad tracks' method

UNIT I LEARNING GOALS -- At the conclusion of this part of the unit, I will be able to:

PART I

1) demonstrate understanding of motion vectors by drawing component vectors for an object's displacement or velocity by hand or by using tools available on Google Slides

2) further demonstrate understanding of vectors by adding basic component vectors together to build a resulting vector OR use a resulting vector to find component vectors by hand or by using tools available on Google Slides

3) find the component vectors of an initial vector given the length of the initial vector and an interior angle using trigonometry

4) Calculate an object's velocity or speed using 4 part FULL WOLGEMUTHIAN system

5) Graph an object's velocity on a displacement vs time graph

6) Graph an object's speed on a distance vs time graph

UNIT I PART I VOCABULARY
TERM
Math Def
SI UNITS
SYMBOL
scalar (A measurement in physics that does NOT require direction)
N/A
N/A
N/A
vector (A measurement in physics that REQUIRES magnitude AND direction)
N/A
N/A
N/A
distance (linear measurement in one dimension)
none
meters
m
displacement ("distance AND direction")
none
meters with direction
m east
average speed (total distance divided by total time)
∆dist/∆t
meters/sec
m/s

velocity ("speed and direction") defined as change in displacement divided by change in time

∆disp/∆t
meters/sec with direction
m/s east
Sine
opp/hyp
sinθ
Cosine
adj/hyp
cosθ
Tangent
opp/adj
tanθ
       
       

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PART II

2) demonstrate understanding of and calculations for an objects' position, displacement, distance, velocity, speed and acceleration in one dimension using appropriate formulae:

For horizontal motion in one dimension:

(v)(t) = x

vf = vi +at

vavg = (vi + vf)/2

xf = xi + vit + 1/2at2

vf2 - vi2 = 2a∆x

For vertical motion in one dimension:

(v)(t) = y

vf = vi +at

vavg = (vi + vf)/2

yf = yi + vit + 1/2at2

vf2 - vi2 = 2a∆y

3) demonstrate understanding of and calculations for an objects' position, displacement, distance, velocity, speed and acceleration in two dimensions using the above formulae in combination

4) demonstrate understanding of and calculations for an objects' position, displacement, distance, velocity and speed and acceleration by analyzing displacement vs time, velocity vs time, or acceleration vs time graphs

UNIT I VOCABULARY
TERM
Math Def
SI UNITS
SYMBOL
instantaneous velocity (velocity of an object at ONE point in time. Often used to find the velocity at ONE point on a curve (See Tangent Line)
∆disp/∆t
meters/sec with direction
m/s east
Average velocity (change in distance/change in time) (velocity of an object between two points in time. Often used to find the velocity between two points on a curve.
∆dist/∆t
meters/sec w/direction
m/s east
Acceleration (change of velocity divided by change in time time)
∆v/∆t
meters/sec2 w/ direction
m/s2 west
Tangent Line: (A line drawn to approximate the slope of a curve at one (and ONLY 1) point on that curve)
N/A
N/A
N/A

A note on subscripts: It is REALLY important in physics to keep track of such things as the initial value for a term and the final value for that same term.

Physicists often use subscripts to assist:

For example: To label an object's final velocity physicists often write: vf

That is pronounced "vee sub f" meaning final velocity.

When working with two dimensions, sometimes it is helpful to keep track of which dimension we're working in. Therefore the initial velocity in the x direction is often written: vfx and is pronounced "vee sub fx" or "vee sub f in the x direction"

Which is an important distinction because falling objects (y direction) behave much differently. So, we might see one of our equations of motion written thusly:

vfy2 - viy2 = 2a∆y

While the horizontal equation of motion would be written:

vfx2 - vix2 = 2a∆x

NOTE on Lab Report Writing:

It's kinduva thing for me: Please use subscripts and superscripts appropriately when typing your lab reports. x2, vi (for example) are REALLY easy to type in Microsoft Word and Google Docs (follow those links to learn how to do that here).

Therefore I will INSIST that you do so.

NEVER, EVER type x^2 when you mean x2 (ever!)

Little Bo Peep Has Lost Her Sheep

and Radar Cannot Find Them

They'll all (face to face)

Meet in parallel Space

Preceding Their Leaders Behind them