Monday, February 9, 2015 Physics & Honors Physics E-Effective Communicators Warm Up A 0.5 kg yoyo spins in circles of radius 0.3m. A student provides an unknown amount of centripetal force to make it spin. The student spins the yoyo 10 times in 30 seconds. Find T, v s , and F c Standards: HS-PS2-1 Analyze data to support the claim that Newton’s second Law of motion describes the mathematical relationship among the net force on a macroscopic object, its mass, and its acceleration RST.11-12.4 Meaning of symbols, key terms, technical jargon WHST.11-12.7: research to aid in problem solving Learning Goal: SWBAT predict and identify how the gravitational force works for objects on earth. Agenda 1. Warm Up 2. Review HW#5 3. #42 Centripetal Force Lab Reflection 4. Bill Nye Gravity on Earth: https Homework G#1 WEEK 23 Notebooks P.7 - Monday P.5 – Tuesday P.4 - Wednesday P.2- Thursday P.1- Friday
Transcript
Monday, February 9, 2015 Physics & Honors Physics
E-Effective Communicators
Warm UpA 0.5 kg yoyo spins in circles of radius 0.3m. A student provides
an unknown amount of centripetal force to make it spin.
The student spins the yoyo 10 times in 30 seconds. Find T, vs,
and F c
Standards: HS-PS2-1 Analyze data to support the claim that Newton’s second Law of motion describes the mathematical relationship among the net force on a macroscopic object, its mass, and its acceleration RST.11-12.4 Meaning of symbols, key terms, technical jargonWHST.11-12.7: research to aid in problem solving
Learning Goal: SWBAT predict and identify how the gravitational force works for objects on earth.
Agenda1. Warm Up2. Review HW#53. #42 Centripetal Force Lab Reflection4. Bill Nye Gravity on Earth: https
Monday February 9, 2015I –Independent Resilient Individuals
Warm UpA 0.5 kg yoyo spins in
circles of radius 0.3m. A student provides an unknown amount of
centripetal force to make it spin. The student spins the yoyo 10 times in 30
seconds. Find T, vs, and F c
Standards: HSPS21-Analyze data to support the claim that Newton’s second law of motion describes the mathematical relationship among the net force on a macroscopic object, its mass, and its acceleration. RST.11-12.9 Synthesize information from a range of sources into coherent understanding of a process, phenomenon, or concept,…WHST.11-12.7: research to aid in problem solving
Learning Goal: SWBAT find the speed of a ball on a string undergoing centripetal motion
Tuesday February 9, 2015I –Independent Resilient Individuals
Warm UpIf you spin a 4 kg mass on a string with a radius
of 2 m 10 times in 20 seconds, find the period of the motion, the speed
of the mass, and the centripetal force acting
on it.
Standards: HSPS21-Analyze data to support the claim that Newton’s second law of motion describes the mathematical relationship among the net force on a macroscopic object, its mass, and its acceleration. RST.11-12.9 Synthesize information from a range of sources into coherent understanding of a process, phenomenon, or concept,…WHST.11-12.7: research to aid in problem solving
Learning Goal: SWBAT find the speed of a ball on a string undergoing centripetal motion
Tuesday, February 10, 2015 Physics & Honors Physics
E-Effective Communicators
Warm Upa. What causes gravity?
b. Name everything you can think of that affects
the strength of the gravitational force
between two objects.
Standards: HS-PS2-1 Analyze data to support the claim that Newton’s second Law of motion describes the mathematical relationship among the net force on a macroscopic object, its mass, and its acceleration RST.11-12.4 Meaning of symbols, key terms, technical jargonWHST.11-12.7: research to aid in problem solving
Learning Goal: SWBAT understand how gravitational force works on earth and connect it to the workings of gravitational force in the starsAgenda1. Warm Up2. Finish Bill Nye Q’s and Discussion3. Gravitational Force Notes4. Gravitational Force #43 activity
HomeworkG#1
Tuesday, February 10th, 2015I –Independent Resilient Individuals
Warm UpIf a 2 kg object spins in a
circle 100 times in 12 seconds, what is its period?
draw it and solve it.
Standards: HS-PS2-1 Analyze data to support the claim that Newton’s second Law of motion describes the mathematical relationship among the net force on a macroscopic object, its mass, and its acceleration RST.11-12.4 Meaning of symbols, key terms, technical jargonWHST.11-12.7: research to aid in problem solving
Learning Goal: SWBAT understand how gravitational force works on earth and connect it to the workings of gravitational force in the stars
Agenda: 1. Warm Up2. Centripetal Force Notes3. Measuring Period Activity #394. Create an experimental
procedure ot find the centripetal acceleration of an object #40
HomeworkG#1
PERIOD 1
Wednesday February 11th, 2015I –Independent Resilient Individuals
Warm UpA 0.5 kg golf ball and a 30 kg bowling ball are
dropped from 1000 feet in the air? What is the
magnitude of the gravitational force
exerted by the objects on the earth? Will these forces significantly affect
the earth’s motion?
Standards: HSPS21-Analyze data to support the claim that Newton’s second law of motion describes the mathematical relationship among the net force on a macroscopic object, its mass, and its acceleration. RST.11-12.9 Synthesize information from a range of sources into coherent understanding of a process, phenomenon, or concept,…WHST.11-12.7: research to aid in problem solving
Learning Goal: SWBAT find the gravitational force between two objects
Agenda: 1. Warm Up2. #43 Finish Bill Nye Video/Activity3. #44 Finish Gravitational activity4. #45 Take Notes, practice finding
the gravitational force between two objects with mass
HomeworkG#2,GH#2
Wednesday February 11th, 2015I –Independent Resilient Individuals
Warm UpWhat do you know
about gravity? Tell me at least 3
things. What don’t you know
about gravity? Tell me one thing. # each
thing for credit
Standards: HSPS21-Analyze data to support the claim that Newton’s second law of motion describes the mathematical relationship among the net force on a macroscopic object, its mass, and its acceleration. RST.11-12.9 Synthesize information from a range of sources into coherent understanding of a process, phenomenon, or concept,…WHST.11-12.7: research to aid in problem solving
Learning Goal: SWBAT understand how gravitational force works on earth and connect it to the workings of gravitational force in the stars
Agenda: 1. Warm Up3. #44 Gravitational Force Notes4.
HomeworkG#1
PERIOD 1
Thursday, February 12th, 2015
E-Effective Communicators
Warm UpFind the force of gravity
between a 2 & 4 kg mass that are 20 m apart? Is the gravitational force between
them strong?
Standards: Analyze data to support the claim that Newton’s second law of motion describes the mathematical relationship among the met force on a macroscopic object, its mass, and its acceleration (CENTRIPETAL)RST.11-12.1 cite specific textual evidence…WHST.11-12.7: research to aid in problem solving.
Learning Goal: SWBAT understand the timeline for the science fair. Agenda: 1. Warm Up2. Review Hw #1 3. Work on assignment #45
HomeworkG#3
Thursday, February 12th, 2015 Physics & Honors Physics
E-Effective Communicators
Warm Upa. What causes gravity?
b. Name everything you can think of that affects the
strength of the gravitational force between two objects
Standards: HS-PS2-1 Analyze data to support the claim that Newton’s second Law of motion describes the mathematical relationship among the net force on a macroscopic object, its mass, and its acceleration RST.11-12.4 Meaning of symbols, key terms, technical jargonWHST.11-12.7: research to aid in problem solving
Learning Goal: SWBAT understand the timeline for the science fair.
Agenda1. Warm Up2. Answer Mousetrap Car Report Questions3. Review Hw 1 & Gravity #444. Watch Bill Nye Intro to Gravity #435. Learn about science fair & pick groups.
HomeworkG#1
Period 1
Friday, February 13th, 2015
I –Independent Resilient Individuals
Warm UpFind the gravitational force
between a 2000 kg object and a 10,000 kg object if they are 10 m apart from each other.
Standards: HS-PS2-1 Analyze data to support the claim that Newton’s second Law of motion describes the mathematical relationship among the net force on a macroscopic object, its mass, and its acceleration RST.11-12.4 Meaning of symbols, key terms, technical jargon
and on mars (amars=3.9 m/s2) if his mass is 65 kg.
Standards: HS-PS2-1 Analyze data to support the claim that Newton’s second Law of motion describes the mathematical relationship among the net force on a macroscopic object, its mass, and its acceleration RST.11-12.4 Meaning of symbols, key terms, technical jargonWHST.11-12.7: research to aid in problem solving
Learning Goal: SWBAT
Agenda: 1. Warm Up2. Review Hw #1 CW#443. Stamp HW 4. #45 Notes5. Work on assignment #45
HomeworkG#2Notebooks Due P.1- Friday
Centripetal Motion & Gravity Test Next Week
Period 1
Symbols, units and equations Sheet
Equations:
Constant Velocity
Constant Acceleration
1.
2.
The Two equations of MotionHorizontal Direction The Two equations of
Motion Vertical Direction
ag=-9.8m/s2
g=9.8m/s2
Fa on b = -F b on a
Forces
Concept symbol units
distance d m
displacement Δx or Δy m
speed vs m/s , km/hr
velocity v m/s, km/hr
acceleration a m/s2, km/hr2 or N/kg
mass m kg
Force F N or kgm/s2
Lab/Engineering Write Up RubricSection 2 1 0
Question/Problem The Lab Question/Design Problem is Stated
Your question/problem solved does not fit with your experiment
Missing
Materials and Procedures/Design Process
The procedures/Design Process is written step by step in complete sentences and the materials are clearly listed.
Procedures/Design Process incomplete or too general or Materials are missing
Procedure/Design Process is missing
Data Collection Contains a table and a graph that represents the data accurately and is labeled correctly
Data table and/or graph is done incorrectly or labeled incorrectly
Either data table or graph is missing.
Calculations Students have all calculations completed, with work shown, and they are correct.
At least half of the calculations are done correctly
1 or more calculations are missing and/or less than half are done correctly and/or work is not shown
Analysis The student gives evidence from their lab data why their hypothesis is true, false, or inconclusive, or why they solved or did not solve their design problems.
The lab write up gives no evidence from their lab data to support evaluate their hypothesis
The hypothesis/design problem is not evaluated.
Conclusion The conclusion includes a summary of your lab results, which discusses any errors in your experiment or difficulties/limitations of your building process.
Sources of error in your experiment or limitations/difficulties in your design process are not discussed.
This section is absent or it is discussed only in the analysis section
CH#5 Finding Centripetal Force.
• Use both v=2πr/T and Fc=mv2/r to solve the following problems.
1. Find the centripetal force of a 1 kg object swinging horizontally with a radius of 1 m and a period of 1s?
2. Find the centripetal force of a 4 kg object swinging horizontally with a radius of 4 m and a period of 0.5s?
3. A 2200 kg car drives on a circular track. If it takes 300s (5 min) to make one lap around the track of radius 2000 m, what is the centripetal Force keeping the car on the track?
4. A wrecking ball on a crane as has mass of 20,000 kg. The crane’s controls malfunction and lock causing the crane and wrecking ball to spin. If the radius of the circle made by the wrecking ball is 500 m, and the period of the spin was 20s, what Centripetal Force must the crane provide so that the wrecking ball will continue spinning and not break and cause chaos in the city?
5. **The centripetal Force caused by a ball swinging on a mass is 200 N. If the mass of the object is 2 kg, and the radius is 20m what is the period of the centripetal motion?
C#5 Finding Centripetal Force.
• Use both v=2πr/T and Fc=mv2/r to solve the following problems.
1. Find the centripetal force of a 1 kg object swinging horizontally with a radius of 1 m and a period of 1s?
2. Find the centripetal force of a 4 kg object swinging horizontally with a radius of 4 m and a period of 0.5s?
3. A 2200 kg car drives on a circular track. If it takes 300s (5 min) to make one lap around the track of radius 2000 m, what is the centripetal Force keeping the car on the track?
4. A wrecking ball on a crane as has mass of 20,000 kg. The crane’s controls malfunction and lock causing the crane and wrecking ball to spin. If the radius of the circle made by the wrecking ball is 500 m, and the period of the spin was 20s, what Centripetal Force must the crane provide so that the wrecking ball will continue spinning and not break and cause chaos in the city?
#41 Centripetal Motion LabObjective: Find the mass of the object spinning in circles.
mb
W=mg
r
binder clip
Trial
mbal
l (kg)
mcli
p
(kg)
W
(total)
(N)
total time (s)
# rev
T(s) rstr+
ball
(m)
v(m/s)
F(N) a(m/s2)
1
2
33. Graph F vs. r (the right 2 columns), find the best fit line, the slope, and the equation of the line.
4. slope = mass of ball so we will compare the mass of the ball measured with the triple beam balance with the slope of our line.
F(N)
a (m/s2)
1. Fill in the table below. Setup will be done together.
Mass of bronze weight:_______kg
#41 Centripetal Motion LabObjective: Find the mass of the object spinning in circles.
mo
bronze weight
r
binder clip
Trial
mobj
(kg)
mclip
(kg)
mbron
ze
weight
(kg)
W=Fc
(N)
total time (s)
# rev
T(s) rstr+b
all (m)
v(m/s)
ac
(m/s2)
1
2
33. Graph Fc vs. ac
, find the best fit line, the slope, and the equation of the line.
4. slope = mass of ball so, measure the mass of the ball with a triple beam balance and then compare it using the following % error equation.
Fc(N)
ac (m/s2)
Theory: In this experimental setup gravity is responsible for the circular motion of the mass. Therefore if we change the gravitational force that the mass experiences, but keep the radius constant we will change the centripetal acceleration of the object. We can ultimately use this data to find the mass of the object.
Centripetal Motion Lab Discussion &
Reflection #42
1.What difficulties did you encounter in the lab?
2. What aspects of the lab seemed to be the most inaccurate?
3. Why did you use a straw in this lab instead of just holding the string and swinging it? 4. How would clamping your fingers over the straw and string affect your data? 5. Explain the process you used to find the period of the centripetal motion.
6. If you increased the radius of your circle, what happened to the centripetal Force? 7. What does v2/r mean? How do you know?
8.Fc=mv2/r is a variation of which important equation we already learned.
Why did we do this lab?
#44 Newton’s Universal Law of
Gravitation
• This is an extension of Newton’s 3rd Law: For every action there is an equal and opposite reaction.
• Gravity is the force of attraction between objects with mass.
• Gravity is always pushing us (or exerting Force on us) towards the center of the earth
We are also exerting an equal and opposite Force on the earth.
Earth
FpersonFearth
Newton’s Law of Universal Gravitation
#44
2kg
2kg
2kg2kg
2kg 4kg
2kg4kg
1.
2.
3.
4.
a. Do you think a larger mass will make the gravitational force weaker or stronger?
b. Do you think a greater distance between the objects will make the gravitational force weaker or stronger? Ultimately predict which single factor has a greater impact on the gravitational force, the mass of an object or the distance between the objects?
c. Rank gravitational force of 1-4, highest to lowest
#45 Newton’s Universal Law of
Gravitation• Specifically this law says:• F=Gm1m2
---------- r2
• Where G is the gravitational constant 6.67x10-11 Nm2/kg2
• m1 and m2 are any two objects with a mass.
• r is the distance between the center of the two objects
• How would you find out whether or not you use Fg=W=mg or Fg=Gm1m2/r2
r
m1
m2
#45 Practice
1.
2.
3.
4.
1m
3m
1m
3m
Find the Gravitational Force of Each. Rank them in order from largest to smallest.2kg 2kg
2kg 2kg
2kg 4kg
4kg
2kg
Gravitational Force # G11. What if any, is the difference between weight and Gravitational
Force? 2. An apple falls from a tree. If the gravitational Force on the apple
is 10N, how much force is the apple pushing the earth with? 3. A 65 kg skydiver is in freefall. What is the Gravitational Force
that the earth is putting on the skydiver? What is the direction of this Force.
4. From problem 3. What is the gravitational Force that the skydiver is putting on the earth? What direction is this Force?
5. With how much Force will Gravity attract a 2000 kg object? 6. How much would a 90 kg person weigh on Mars? (ag=3.9m/s2)
7. From Problem 6. What is the Gravitational Force between the person and the planet?
Newton’s Law of Gravitation Practice
HG#2Use this equation for the following problems: F=(Gm1m2)/r2 G=6.67x10-11Nm2/kg2
2. Find Fg.m1=4x104kgm2=8x106kgr=4x104m
1. Find Fg.M1=2kgM2=7kgR=500m
3. Find Fg.M1=5x1024 kgM2=9x1018 kgR=3x105 m
5. A 6kg object and a 20 kg object are separated by 50 m. What is the gravitational Force between the two masses?6. From problem 5, how fast will the 6kg object accelerate towards the 20 kg object?
4. Find R.M1=5x105 kgM2=4x1010 kgFg= 4x103 N
Newton’s Law of Gravitation Practice G#2
Use this equation for the following problems: F=(Gm1m2)/r2 G=6.67x10-11Nm2/kg2
b. Find Fg.m1=4x104kgm2=8x106kgr=4x104m
a. Find Fg.M1=2kgM2=7kgR=500m
c. Find Fg.M1=5x1024 kgM2=9x1018 kgR=3x105 m
1. A 6kg object and a 20 kg object are separated by 50 m. What is the gravitational Force between the two masses?
Gravitational Force Practice G#3
1. What is the force of attraction (gravitational force) between two people if one person is 85 kg and the other is 72 kg and the two people are 2 m away from each other?
2. If one person (70kg) is in Los Angeles and another(70kg) is in Bejing 1x107 m away, what is the force of attraction between the two people?
3. Find the force of gravity exerted on a 55 kg (121 lb) person lying 0.1 meters below a 200,000kg (90,000 lbs) train.
4. If an astronaut landed on the surface of Mars, what would the Force of Gravity be on a person with a mass of 75kg (165lbs) if Mars has a mass of 6.42x1023kg and a radius of 3.37x106m?
Gravity & Circular Motion
From learning about Gravity, we know:1. Objects in space with a large enough speed will orbit
the earth or other large objects at a constant speed.2. As long as nothing causes the object to lose speed it
will orbit the earth forever. 3. The object stays at the same distance from the earth
throughout the circular orbit. From learning about Centripetal Motion, we know:4. The speed of the object will always be perpendicular
to the direction of the force of gravity.5. When Gravity makes objects orbit other objects in a
circle, gravity is acting as a Centripetal Force.
#43 Bill Nye Video Questions
1. What does gravity do? Give 3 examples2. Who was the first scientist to experiment with
falling objects? 3. What did this scientist discover?4. What will happen to a feather and hammer if you
dropped it on earth? What happened on the moon?
5. Challenge: How can gravity be responsible for making things fall to the ground and for making planets orbit around the sun? Give an explanation.
#46 Gravitational Force & Acceleration in South
GateNow that we understand what gravitational force is and how to calculate it, we are going to extend our new knowledge to find the exact acceleration due to gravity in South Gate and we’ll compare it to Mount Everest.
Theory: Gravity is supposed to be weaker in South Gate than Mt. Everest because of Mt. Everest’s higher elevation. Does it really make much difference though?
- We know how to calculate the force of gravity between 2 objects, for example Mr. A and the Earth.
- What can we do with that force find out the value what we consider gravity, g= 9.8m/s2 ?
- Hopefully you’re thinking Fnet=ma. If we put the gravitational force into this equation in place of Fnet, then the a will be acceleration due to gravity, or g.
southgate
mearth
Instructions: a. Create a data table with mmr. , mearth, rsg,
rev Fsg, Fev, asg, aev
b. Look up the mass and radius of the earth online or in one of the textbooks.
c. Look up the elevation (height) above sea level for South Gate and Mt. Everest.
d. Find the distance between the center of the earth & the center of Mr. A (height 1.92m, mass 65kg) if he were in South Gate or Mt. Everest.
e. Calculate the Force of gravity in South Gate & Everest
f. Calculate the Acceleration due to gravity in South Gate and Everest.
everestrsg
rev
mmr.a
mmr.a
(Don’t Forget to convert km ->m)
GH#4 Gravitational Force &
Acceleration
a. - me=5.97x1024kg
- mperson =72 kg
- r=6.371x106 m - Fg=?
- ag=?
b. - me=5.97x1024kg
- mcar =1000 kg
- r=6.371x106 m - Fg=?
- ag =?
use F=Gm1m2/r2 & Fnet=ma to solve the problems below along with G=6.67x10-11 Nm2/kg2
c. - me=5.97x1024kg
- minsect = 0.001 kg
- r=6.371x106 m - Fg=?
- ag =?
1. After calculating Fg and ag for a,b, & c , what pattern did you notice?2. What variable in a,b, & c did not affect the how fast the object would
accelerate if it was falling to the ground?3. The class takes a trip to Griffith park. At Griffith Park’s highest point
it is 495.3 m. The mass and radius of the earth are 5.97x1024kg and 6.371x106 m. What is the acceleration due to gravity if an object of any mass is placed at that point? (Remember your answer from #2, knowing that will help you solve this)
G#4 Gravitational Force &
Acceleration
a. - me=5.97x1024kg
- mperson =72 kg
- r=6.371x106 m - Fg=?
- ag=?
b. - me=5.97x1024kg
- mcar =1000 kg
- r=6.371x106 m - Fg=?
- ag =?
use F=Gm1m2/r2 & Fnet=ma to solve the problems below along with G=6.67x10-11 Nm2/kg2
c. - me=5.97x1024kg
- minsect = 0.001 kg
- r=6.371x106 m - Fg=?
- ag =?
1. After calculating Fg and ag for a,b, & c , what pattern did you notice?2. What variable in a,b, & c did not affect the how fast the object would
accelerate if it was falling to the ground?3. The class takes a trip to Griffith park. At Griffith Park’s highest point
it is 495.3 m. The mass and radius of the earth are 5.97x1024kg and 6.371x106 m. What is the acceleration due to gravity if you place an object
a. of 1kg mass at that point? b. of 100 kg mass at that point?
