Okay, let's break this down step-by-step: 1) Have your friend hold the meter stick vertically between your thumb and index finger, with the zero mark between your fingers and the 1 mark above. 2) Get ready to catch the stick without moving your hand. 3) When your friend drops it, catch it as quickly as you can. 4) Record the mark it falls to. Do this 5 times and average the distances. 5) Use the equation d = 1/2 * a * t^2 to calculate your reaction time t, where a is 9.8 m/s^2 and d is the average distance in meters. Let me know if you need any help with the

1. G WHIZ LAB
• Grades are curved: graded out of 28 points instead of 33
Does a more massive object fall faster than a less massive
one?
Were you able to calculate acceleration due to gravity close to
the accepted value?

2. LAB REPORT COMMENTS
Experimental Design
Problem Definition Section • Materials and safety notes
• Problem statement: What are we trying • Make sure to list at least 2-3 safety notes for
to do in this lab? the lab
• Constants in this lab?
• Prove the accepted value of
gravity: 9.81 m/s2 • Time interval, dot timer used, if person
dropping/holding dot timer were the
• See if mass affects acceleration same, possibly length of tape was held
constant
due to gravity
• Some people put gravity as constant – this is
• Hypothesis should address the what we are trying to prove in this lab though
problem statement(s) • Procedure should be stated in sufficient detail
so that it could be reproduced
• What side of the dot timer were the washers?
• How was the dot timer held when paper was
dropped through?
• Draw pictures of procedures if necessary

3. LAB REPORT COMMENTS
• Data Presentation Section
• Include a “data presentation” section in report. Tell reader to see attached tables & graphs if they are
attached at the back of the lab report
• Tables
• Add a border and center text for tables done on excel
• Title tables
• Calculations & Equations used
• Include this information here instead of in discussion & conclusion section
• First show equations, then sample calculations using those equations
• Show one sample calc for all calculations done
• Graphs
• Make sure to give a descriptive title to graphs (not just the default title given by excel)

4. Conclusion
• Be explicit about how IV affected DV…”The IV, which was the
# of washers, had an affect on the DV, the distance between
LAB REPORT COMMENTS dots…”
• Refer back to your hypothesis: were your right?
Discussion Questions • Refer to specific data collected: a specific table or data
point in graph; use this information to support your conclusion
• Make sure to answer questions so that reader
knows question without looking at question. • Validity: Can someone reproduce this lab and get the same
results? Were there major errors that invalidate your data?
• Use data to support your answers • Were the # of trials appropriate for this lab?
• Do not show calculations in this section, just • Were the procedures followed through consistently ?
Were things held constant that should have been? Or
refer to data to support your answer. should other things have been held constant that were
not?
• #4: Must divide the time by 60. What should
the area under the velocity vs. time graph give • What errors may have occurred? How can you prevent them?
you? • What improvements would you make in the lab in the future to
make the lab more valid/repeatable? How would you extend
• Many people did not even calculate this lab?
acceleration due to gravity – must calculate it • Wrap up lab, and connect this lab to an everyday situation.
in order to do #1 and 5. • Some people did not even tell what their calculated gravity
values were at all in the report! Must calculate it and discuss
your results!

5. UNIT 3: VECTORS
& PROJECTILE
MOTION
• How would you describe
to someone how to get
from MHS to Catsup &
Mustard?

6. Scalar Magnitude
SCALAR Example
A SCALAR is ANY quantity Speed 20 m/s
in physics that has
MAGNITUDE, but NOT a Distance 10 m
direction associated with
it.
Time 25 seconds
Magnitude – A numerical
value with units.
Heat 1000
calories
*a scalar item in your text
is written in italics.
s, d, m, t

7. VECTOR
A VECTOR is ANY quantity Vector Magnitude
in physics that has BOTH & Direction
MAGNITUDE and Velocity 20 m/s, N
DIRECTION.
Acceleration 10 m/s/s, E
Force 5 N, West
* A vector quantity in your
textbook are denoted in We will use an an ARROW above the variable

bold text to show a variable is a vector. The arrow is used
   to convey direction and magnitude.
v, x, a, F

8. VECTOR Example 1: Mike skipped towards the
east at 25 meters/second.
• Drawing pictures of physical
situation is very helpful when
solving vector problems
• Vectors represent by arrows
• Point in direction of vector Scale: 1 block = 1 m/s
• Length of arrow = magnitude
of vector Example 2: Taylor pranced north for 40
meters.
• Use a scale to do this – usually
use a ruler
Scale: 1 block = 1 m

9. APPLICATIONS OF VECTORS
VECTOR ADDITION – If 2 similar vectors point in the SAME direction,
add them.
• Example: A man walks 54.5 meters east, then another 30 meters
east. Calculate his displacement relative to where he started?
54.5 m, E + 30 m, E Notice that the SIZE of the
arrow conveys MAGNITUDE
and the way it was drawn
84.5 m, E conveys DIRECTION.
This is the resultant
displacement

10. APPLICATIONS OF VECTORS
VECTOR SUBTRACTION - If 2 vectors are going in opposite directions, you SUBTRACT.
• Example: A man walks 54.5 meters east, then 30 meters west. Calculate his
displacement relative to where he started?
54.5 m, E
-
30 m, W
24.5 m, E

11. a2 + b2 = c2 OR
NON-COLLINEAR VECTORS Opposite2 + adjacent2 = hypotenuse2
• Vectors have both horizontal and vertical Sinθ = opposite
components hypotenuse
• Horizontal is usually the east or west
directions, right or left Cosθ = adjacent
hypotenuse
• Vertically is usually the north or or
down
tanθ = adjacent
• Use pythagorean theorem and opposite
trigonometry (SOHCAHTOA!) to solve
hypotenuse
opposite
Θ
adjacent

12. NON-COLLINEAR VECTORS: DRAW A DIAGRAM
What do vectors look like graphically in physics?
A man walks 95 km, East then 55 km, north.
The hypotenuse in Physics is Finish
called the RESULTANT.
55 km, N
Vertical
Component
Horizontal Component
95 km,E
Start NOTE: When drawing a right triangle that conveys
some type of motion, you MUST draw your
components TAIL TO TIP.
The LEGS of the triangle are called the COMPONENTS

13. NON-COLLINEAR VECTORS: SOLVING
MATHEMATICALLY
Let’s solve this problem: A man walks 95 km, East then 55 km, north.
Calculate his RESULTANT DISPLACEMENT.
When 2 vectors are perpendicular, you
must use the Pythagorean theorem.
Finish
RESULTANT.
c 2 = a 2 + b2 ® c = a2 + b2
55 km, N c = Resultant = 952 + 552
Vertical
Component
c = 12050 = 109.8 km
Horizontal Component
95 km,E
Start

14. BUT……WHAT ABOUT THE DIRECTION?
In the previous example, DISPLACEMENT was asked for and since it is a VECTOR we
should include a DIRECTION on our final answer.
N
W of N E of N
N of E
N of W
W E
N of E S of W S of E
W of S E of S
S

15. BUT…..WHAT ABOUT THE VALUE OF THE
ANGLE???
Just putting North of East on the answer is NOT specific enough for
the direction. We MUST find the VALUE of the angle.
SOHCAHTOA!
Sinθ = opposite
hypotenuse
hypotenuse
opposite Cosθ = adjacent
hypotenuse
tanθ = adjacent
opposite
adjacent

16. BUT…..WHAT ABOUT THE VALUE OF THE
ANGLE???
To find the value of the angle we will use a Trig function called TANGENT.
109.8 km
55 km, N
opposite side 55
Tan 0.5789
N of E adjacent side 95
95 km,E Tan 1 (0.5789) 30
So the COMPLETE final answer is : 109.8 km, 30 degrees North of East

17. VECTORS: SOLVING PROBLEMS GRAPHICALLY
We have been solving vector Example: A man walks 95 km, East then 55 km, north.
problems mathematically, Calculate his RESULTANT DISPLACEMENT and angle.
but they can also be solved
graphically, using a ruler
and protractor.
Steps:
1. Develop a scale to use to
draw the problem.
2. Draw the vector
graphically.
3. Solve for unknowns, using
a protractor and ruler.

18. HOMEWORK SOLUTIONS: SOLVING GRAPHICALLY
Page 1: Using a ruler and protractor to find • Page 2: Finding the resultant vectors
horizontal and vertical components of a vector: given its components:
• Vertical: 10.8 cm 1. 6.4 cm at 51 degrees above
Horizontal
• Horizontal: 10.0 cm
2. 11.7 cm at 59 degrees below the
• 44.5 degrees
horizontal
• Magnitude: 14.2 cm

19. EXAMPLE: BREAKING A VECTOR INTO ITS
COMPONENTS
Suppose a person walked 65 m, 25 degrees East of North. What were
his horizontal and vertical components?
H.C. = ?
The goal: ALWAYS MAKE A RIGHT TRIANGLE!
V.C = ? To solve for components, we often use the trig functions
25° 65 m sine and cosine.
adjacent side opposite side
cosineq = sineq =
hypotenuse hypotenuse
Rearranging these equations to solve for the horizontal and
vertical components…
adj = hypcosq opp = hypsin q
adj = V.C. = 65cos25 = 58.91m, N
opp = H.C. = 65sin 25 = 27.47m, E

20. EXAMPLE
A bear, searching for food wanders 35 meters east then 20 meters north.
Frustrated, he wanders another 12 meters west then 6 meters south.
Calculate the bear's displacement.
Step 1: Draw a diagram of the bear’s displacement. 23 m, E
Step 2: Find the resultant displacement in the north
- =
direction & east direction. Draw This triangle.
Step 3: Solve for the bear’s magnitude and direction.
12 m, W
- =
6 m, S 14 m, N
20 m, N
35 m, E R 14 m, N R = 14 2 + 232 = 26.93m
14
Tanq = = .6087
23
23 m, E
q = Tan -1 (0.6087) = 31.3
The Final Answer: 26.93 m, 31.3 degrees NORTH or EAST

21. EXAMPLE 1: SOLVE FOR RESULTANT VECTOR
A boat moves with a velocity of 15 m/s, N in a river which flows
with a velocity of 8.0 m/s, west. Calculate the boat's resultant
velocity with respect to due north.
Rv 82 15 2 17 m / s
8.0 m/s, W
15 m/s, N
8
Tan 0.5333
Rv 15
Tan 1 (0.5333 ) 28 .1
The Final Answer : 17 m/s, @ 28.1 degrees West of North

22. EXAMPLE: RESOLVE A VECTOR INTO ITS COMPONENTS
A plane moves with a velocity of 63.5 m/s at 32 degrees South of East.
Calculate the plane's horizontal and vertical velocity components.
adjacent side opposite side
cosine sine
H.C. =? hypotenuse hypotenuse
32° adj hyp cos opp hyp sin
V.C. = ?
63.5 m/s
adj H .C. 63.5 cos32 53.85 m / s, E
opp V .C. 63.5 sin 32 33.64 m / s, S

23. EXAMPLE: ADDING TWO VECTORS AT DIFFERENT
ANGLES.
A storm system moves 5000 km due east, then shifts course at 40
degrees North of East for 1500 km. Calculate the storm's resultant
displacement graphically, and mathematically.
adjacent side opposite side
cosine sine
1500 km hypotenuse hypotenuse
V.C.
adj hyp cos opp hyp sin
40
5000 km, E H.C.
adj H .C. 1500 cos 40 1149.1 km, E
opp V .C. 1500 sin 40 964.2 km, N
1500 km + 1149.1 km = 2649.1 km R 2649.12 964.2 2 2819.1 km
964.2
Tan 0.364
2649.1
R
964.2 km Tan 1 (0.364) 20.0
2649.1 km
The Final Answer: 2819.1 km @ 20 degrees, East of North

24. VECTOR ACTIVITY: MEASURING BEYOND THE
METER STICK ACTIVITY

25. MEASURE YOUR REACTION TIME!
Reaction time affects your performance in many things that you do in life…so…
Today you will determine your reaction time!
1. Have a friend hold a meter stick vertically between the thumb and index finger of your
open hand. Meter stick should be held so that the zero mark is between your fingers with
1 mark above it. Do not touch meter stick, let it fall freely. Your catching hand should be
resting on a table
2. Without warning, your friend will drop the meter stick so that it falls between your thumb
and finger. Catch the meter stick as quickly as you can!
3. Record the distance the meter stick falls through your grasp. Do this five times.
4. Calculate your average reaction time from the free fall acceleration and the distance you
measure.