Youngstown City Schools
SCIENCE: PHYSICS
UNIT #2: INTRODUCTION TO MOTION- - (6 Weeks) 2013-2014
SYNOPSIS: This unit focuses on the concepts and relationships of displacement, time, speed, and velocity. Students
explore freely falling bodies as examples of motion with constant acceleration. They collect and use data to construct and
interpret graphs. Students demonstrate their knowledge of physics and engineering concepts by designing and building their
own working small scale roller coaster that contains vertical and horizontal loops, bunny hills, and jumps.
ENABLERS: acceleration, average acceleration, average velocity, constant acceleration, displacement, free
fall, free-fall acceleration, velocity, and force
STANDARDS
IV. MOTION
A. Use and apply the laws of motion to analyze, describe and predict the effects of forces on the motions of
objects mathematically.
B. Analyze velocity as a rate of change of position with regards to average velocity and instantaneous velocity.
C. Compare and contrast speed, velocity, distance and displacement as scalar and vector quantities.
D. Analyze acceleration as rate of change in velocity.
E. Use graphical and mathematical tools to design and conduct investigations of linear motion and the
relationships among position, average velocity, instantaneous velocity, acceleration and time.
F.
Graph and interpret graphs on position vs. time, velocity vs. time, and acceleration vs. time.
G. Instantaneous velocity for an acceleration object can be determined by calculating the slope of the tangent
line for some specific instant on a position vs. time graph.
H. Introduction of complex graphs that have both positive and negative displacement values and involve motion
that occurs in stages. Symbols representing acceleration are added to motion diagrams.
I.
The determination of uniform acceleration including free fall (initial velocity, final velocity, time, displacement,
acceleration, average velocity).
J.
Interpreting graphs for average velocity, instantaneous velocity, acceleration, displacement, and change in
velocity.
LITERACY STANDARDS
RST.4 Determine the meaning of symbols, key terms, and other domain-specific words and phrases as they are used in a
specific scientific or technical context relevant to grades 11–12 texts and topics.
WHST.6 Use technology, including the Internet, to produce, publish, and update individual or shared writing products in
response to ongoing feedback, including new arguments or information.
WHST.7 Conduct short as well as more sustained research projects to answer a question (including a self-generated question)
or solve a problem; narrow or broaden the inquiry when appropriate, synthesize multiple sources on the subject, demonstrating
understanding of the subject under investigation.
WHST.9 Draw evidence from information texts to support analysis, reflection, and research.
TEACHER NOTES
MOTIVATION
1. A demonstration on displacement (Holt Physics TE page 42, demonstration 1).
2. A demonstration on acceleration (Holt Physics TE page 48, demonstration 2).
3. Distance learning activity on the physics of roller coasters
4. Students set both personal and academic goals for this Unit.
5. Preview the authentic assessment
7/082013
YCS Science: PHYSICS - Unit 2 - - INTRODUCTION TO MOTION 2013-2014 1
TEACHING-LEARNING
TEACHER NOTES
1. Students (a) calculate their reaction time in catching a meter stick that is falling; (b)
analyze and graphically show the results of the activity; (c) make hypotheses about
reaction time (e.g., left handed people have faster reactions than right handed people,
etc.). Students design, and carry out their experiments, gather and present data
graphically, and explain clearly and concisely the results of their experiment to the class.
If their conclusions are different than their hypotheses, they revise their experiment to
gather new data. (WHST.7) (IVB,IVI)
2. Teacher explains the relationships between displacement, time, speed, and velocity.
Students complete practice problems on these concepts. Students break into small
groups and analyze each other’s practice problems for accuracy, technique, correct
formula use, and thought processes. Teacher leads discussion on correctness of the
calculations. Use remediation as necessary. (IVC,IVF) (RST.4)
3. Teacher demonstrates the difference between accelerated and non-accelerated motion
by walking around the room. Ask students to identify when the motion is accelerated and
when it is uniform. Students take notes and generate questions for discussion. (IVD)
4. Students read and discuss information on the design of roller coasters to broaden their knowledge base on roller coaster
forces by exploring the information on the following websites:
http://library.thinkquest.org/C005075F/English_Version/Designing%20the%20Roller%20Coaster.htm)
http://www.math.wpi.edu/Course_Materials/Calc_Projects/node6.html
http://www.math.wpi.edu/Course_Materials/Calc_Projects/node6.html
(WHST.7) (IVA, B, C)
5. Students demonstrate how to design and build a roller coaster to determine, speed and
velocity of a marble. They graph their results for different points on the coaster. (e.g., top
of first hill, bottom of first hill, etc.) (IVC, F, G, H, I) (WHST.6, WHST.7)
6. Teacher demonstrates the relationship between the direction and the magnitude of a
force (Holt Physics TE page 126, demonstration 2). (IVA, IVB) (RST.4) Students solve
practice problems. Follow with a class discussion focusing on key terms, as they are used
in this context.
7. Students calculate and graph the acceleration of a vehicle down slopes of different
heights and lengths. Teacher leads a discussion of the class results. (IVE, IVF) WHST.7)
8. Teacher explains uniform acceleration and how to calculate the initial velocity, final
velocity, average velocity, and acceleration. Students practice problems and then use this
information to determine and graph the velocity of an egg in the egg drop experiment
(IVG,IVH, IVI, IVJ) (WHST.7, WHST.9)
9. Students use egg drop data to calculate acceleration and final velocity of the egg
apparatus. (attached page 4-5) Class discussion follows.
10. Students complete lab “Mousetrap Racers” attached on pages 6-9
TRADITIONAL ASSESSMENT
TEACHER NOTES
1. Unit Test: Multiple Choice and 2/4 point response questions
TEACHER CLASSROOM ASSESSMENT
TEACHER NOTES
1. Lab reports or practical reports using rubrics for quality points
7/082013
YCS Science: PHYSICS - Unit 2 - - INTRODUCTION TO MOTION 2013-2014 2
2. Assignments and in class work
AUTHENTIC ASSESSMENT
TEACHER NOTES
1. The students demonstrate their knowledge of physics and engineering concepts by
designing and building their own working small scale roller coaster, with teacher supplied
materials that contain vertical and horizontal loops, bunny hills, and jumps.
2.
Students evaluate their goals for the Unit.
3. Students demonstrate their knowledge of physics and engineering concepts by designing
a roller coaster on an IPAD or computer simulator to test for speed, velocity, and g-forces.
7/082013
YCS Science: PHYSICS - Unit 2 - - INTRODUCTION TO MOTION 2013-2014 3
Name _____________________________
Parachute Egg Drop
Objectives: Students will drop parachuted eggs to demonstrate the concepts of gravity, air resistance, and terminal
speed. Students will construct distance and velocity graphs to interpret the acceleration of an object.
Pre-Lab Theory
Gravity is the force of attraction that causes objects to fall toward the center of the earth. Air resistance, or air
friction, can slow down the acceleration of a falling object.
The area “fronting the wind” affects the amount of air resistance a falling object encounters. Terminal speed is the
speed at which the downward pull of gravity is balanced by the equal and upward opposing force of air resistance for
a falling object.
Materials

Lightweight plastic kitchen garbage-can liners; Scissors; Ruler; 20-inch lengths of light string; 3 plastic sandwich
bags; 3 raw eggs
Procedures
1. From a lightweight plastic kitchen garbage-can liner, cut out three squares. Make one square 10” x 10”, a
second square 20” x 20”, and a third square 30” x 30”.
2. Make a parachute out of each square by tying a piece of string to each corner of the square, then attaching the
other ends of the strings to a plastic sandwich bag.
3. Place a raw egg in each of the sandwich bags.
4. Predict which egg has the best chance of surviving a drop from about ten feet from the floor. Explain the
reasoning behind their predictions.
5. Drop each unfurled egg parachute from a height of ten feet, and then determine whether or not your predictions
were confirmed.
Discussion Questions
1. Describe the changing forces that acted on the parachutes as they fell and the resulting changes in the
parachutes’ motion. How did the falls of the larger parachutes differ from the falls of the smaller ones?
2. Construct a distance vs. time graph for the following data: (D1 = 0 m, T1 = 0 sec), (D2 = 7 m, T2 = 3 sec), (D3 = 14 m,
T3 = 6 sec), (D4 = 21 m, T4 = 9 sec), and (D5 = 28 m, T5 = 12 sec). Discuss how you would use this graph to determine the
speed of the object being represented. Is the object moving with constant speed or constant acceleration? Explain
how you arrived at your conclusion.
From the graph constructed in question 1, calculate the object’s speed at three-second intervals, and then use this
new information to construct a velocity vs. time graph for the object.
7/082013
YCS Science: PHYSICS - Unit 2 - - INTRODUCTION TO MOTION 2013-2014 4
Parachute Egg Drop
Distance
Time
Velocity
10” x 10”
20” x 20”
30” x 30”
10” x 10”
20” x 20”
30” x 30”
10” x 10”
20” x 20”
30” x 30”
7/082013
YCS Science: PHYSICS - Unit 2 - - INTRODUCTION TO MOTION 2013-2014 5
Acceleration
Physics Mousetrap Racers
Situation: Your mission is to design and construct a car powered by a
standard-size mousetrap. Most people choose four-wheeled cars, but
three-wheeled cars also exist. Some ways to increase your distance are
replacing the string that pulls the axle with a rubber band. Larger
wheels will increase the distance obtained using the same amount of
energy. Using more string than what is needed will cause the string to
rewind around the axle after the string runs out.
Problem: The objective is to design the lightest possible device that
can travel at least 50 feet.
Pre-Lab Theory: A mousetrap is powered by a helical torsion spring.
Torsion springs obey an angular form of Hooke's law:
where
is the torque exerted by the spring in Newton-meters, and is the
angle of twist from its equilibrium position in radians.
is a
constant with units of Newton-meters / radian, variously called the
spring's torsion coefficient, torsion elastic modulus, or just spring
constant, equal to the torque required to twist the spring through an
angle of 1 radian. It is analogous to the spring constant of a linear
spring. The energy U, in joules, stored in a torsion spring is:
When a mousetrap is assembled, the spring is initially
twisted beyond its equilibrium position so that it applies significant
torque to the bar when the trap is closed.
The mousetrap bar travels through an arc of approximately 180
degrees. This motion must be used to turn the car's axle or wheels.
The most common solution is to attach a string to the bar and wrap it
around an axle. As the bar is released, it pulls on the string,
causing the axle (and wheels) to turn. Tying the string directly to
the mousetraps bar, however, will not make good use of the energy
stored in the spring. The distance between the opened and closed
positions of the bar of a mousetrap is typically 10 cm, so this is how
much string would be pulled. Wrapped around even a small diameter
axle, this amount of string will not create enough revolutions to move
the car as far as it might go. To get around this problem, most
mousetrap cars add a lever to the bar so that the lever will pull a
much greater length of string and cause the axle to turn many more
revolutions.
7/082013
YCS Science: PHYSICS - Unit 2 - - INTRODUCTION TO MOTION 2013-2014 6
Another reason to add a lever to the mousetrap bar is to reduce
the amount of torque applied to the wheels. If too much torque is
applied to the wheels, the force between the wheels and the ground
will exceed the maximum frictional force due to the coefficient of
friction between the wheel and ground surfaces. When this happens, the
wheels slip and energy stored in the spring is wasted. Using a long
lever on the mousetrap bar reduces the tension in the string due to
the spring's torque, and thus reduces the torque applied to the car's
wheels. In addition to reducing the torque applied to the wheels, the
coefficient of friction may be improved by using higher friction
materials, such as rubber, on the wheels.
Design Constraints

The Mousetrap car must be initially powered by the Mousetrap
mechanism.
 The initial energy may be transferred to another device ONLY if that
device does not produce energy by itself.
 NO other energy source may be added (e.g. CO2 cartridge, battery,
etc.)
 The mousetrap must be permanently mounted to the chassis.
 All Mousetrap Cars must be made by students. No pre-constructed
materials allowed.
Suggested Materials:
Mousetrap (provided), pens, eye hooks, CDs, vinyl record albums,
string, clay or axle clogs (wheel kit), wheel axles, scraps of wood,
glue, empty thread spools or other large circular item, balsa wood,
metal rods, washers
Competition
1. Each car will use ONLY one standard size mousetrap.
2. The distance that a car travels will be measured to the point where
the car leaves the designated track area from the starting line to
the wheel closest to the starting line.
3. Each Mousetrap Car will be allowed 2 trials. The BEST will be
recorded in a single run.
4. Each car must be ready for competition when called.
5. If you are not ready/prepared to race, you will forfeit your turn.
6. Two forfeits equal a disqualification.
7. Each car will be assigned a random number and there will be two
rounds of trials.
Awards
Most Creative (most unique design): First, second, and third place.
Mechanical Design: First, second, and third place.
Distance Traveled Up Farthest: First, second, and third place.
7/082013
YCS Science: PHYSICS - Unit 2 - - INTRODUCTION TO MOTION 2013-2014 7
7/082013
YCS Science: PHYSICS - Unit 2 - - INTRODUCTION TO MOTION 2013-2014 8
7/082013
YCS Science: PHYSICS - Unit 2 - - INTRODUCTION TO MOTION 2013-2014 9