FarleyPhysics.com

Create a 9 square comic about electric fields:

Note, to take a picture of a simulation or anything on the screen, press Command-shift-4 and drag a box around what you want.  The image will appear on your desktop.  Use the simulations from the past week: Balloon and Sweater, Electric Field Hockey, Field Lines and Field Strength, 2D Electric Field, 3D Electric Field, Orbits, or do a google search for the image.

Square 1 Comic title: “Electric Fields” real large with the image of an electric field behind it.

Square 2. The field from a positive charge, text explaining what direction the field lines point.

Square 3. The field from a negative charge, text explaining what direction the field lines point.

Square 4. The field from a dipole (one positive and one negative charge), text should explain what a dipole is.

Square 5. Likes repel (explain it with an image and text)

Square 6. Opposites attract (explain it with an image and text)

Square 7. Rubbing a balloon against a sweater, what happens?

Square 8. Bringing a charged balloon next to a wall, what happens? (use command-shift-4 to screenshot yesterday’s simulation).

Square 9. Show the highest level you can reach with Electric Field Hockey.  Show it with Trace on and Field on.

Print your comic to Mr. Farley’s Printer and put it in your notes.

Page 3 in your notes is all about the electric field.

1. Download the Electric Field  chapter of my book here: Electric Field by Tony Farley

2. Read the Electric Field section (Section 2)  and answer the questions at the end.  Put all questions, answers, and drawings in your notes.

1. Electrostatics demonstration.  Upward lightning, Toronto Lightning storm, slo mo lightning, Tesla coils at Coachella

2. Run this simulation to answer the following questions:

1. Click the Add button to add a charge.  Draw the field with the arrows an charge in your notes.  Is the charge positive or negative?  Click Properties to see if you are right.

2. Click Add to add another charge and explain what happens.  Do they attract or repel each other?  Is the new charge positive or negative?  How do you know?

3. Reset, then add a negative and a positive charge. Do the charges repel or attract each other?  Pause the simulation when the charges are far apart from each other and draw the charges and field in your notes.  Label which charge is positive and which is negative.

4. Reset, grab the External Field arrow and have the field point to the right.   Add  a negative charge.  Explain where the charge moves.   (in the direction of the field or opposite?).  Draw a picture and write this as a statement in your notes that will help you remember it on a quiz.

5. Reset and add a positive charge.  Make the external field point to the right and explain where the charge goes.

6. Answer the following question: ______ charges move in the same direction as an electric field and _________ charges move in the opposite direction a field is pointing.

3. Static Shock!

Run this simulation to see how static shocks work.

What happens when you rub John’s foot on the floor?

What happens to the charge when you bring John’s finger near the door handle?

4. Hockey

Play Electric Field Hockey and see what level you can reach.  Draw level one in your notes, with all the charges, the field arrows, and show the path of the puck.

1. Download and read the chapter on Charge in my book: charge-by-tony-farley

2. Answer the questions at the end of the chapter in your notes.

Run this simulation and answer the following questions in your notes.

1. Click on the “Charts” tab.  Give the man 5 m/s of velocity and run the simulation.  Draw the Position vs. time graph of his motion before he hits the wall in your notes.  Title your graph “Position vs. Time of a man moving at 5m/s constant velocity.

2. Draw the velocity vs. time graph and label it.

3. What is the acceleration of a flat velocity vs. time graph like the one in #2?

4. Reset all the settings by clicking “Reset All.”  Now give the man an acceleration of 2 m/s^2.  Draw the Position vs. Time graph and title it properly.

5. Draw the Velocity vs. time graph.  What does this graph tell you about how the velocity changes.

6. Use this simulation to fin the acceleration of a woman pushing a 20kg cart with 40N of force.  Draw the dots that show her position vs. time.

7. Use this simulation to find out how long it takes a 5 m high ball to fall to the ground.  Be sure to set g = 10.

8. Use this simulation to find the angle that makes the projectile reach the furthest from where it started and what angle makes it reach the highest.  Draw the two projectile paths in your notes.

9. Use this page to draw the free body diagram of a book on a table, a girl hanging by two ropes, and an egg free-falling.

10.

1. Scientific Notation and Gravitation Equation Notes (Page6)

2. (Page 7)

Today’s lesson uses the Newton’s Law of Gravity Calculator.

Relationship between mass and gravitational force.

1. What is the gravitational force on an apple at the surface of the earth?

2. If you increase the mass of the apple by x2, what is the gravitational force?

3. If you increase the mass of the apple again by x2, what is the gravitational force?

4. Describe the relationship between the mass of the object and the gravitational force on it.

Relationship between radius and gravitational force.

1. What is the gravitational force between a 1 kg mass and the earth, at the radius of the earth?

2. If you increase the radius by x2, what is the gravitational force?

3. Reset the radius so it is back to 6.37 x10^6 meters.  Increase the radius x3.  What’s the gravitational force?

4. Explain the relationship between radius and gravitational force.

Different masses

1. What is the force of gravity between two people who are 1m away from each other?  Is this force strong or weak?

2. What’s the force of gravity between a person and the earth on the surface of the earth?

3. What is the force of gravity between the earth and the sun at the distance to the sun?

4. What is the force of gravity between the earth and moon at the distance to the moon?

5. What force is stronger, the force between the earth and sun or the earth and moon?

6. Answer the question here and list the items in order of increasing strength.  Write your explanation for why they are in that order.

7. Answer the question here, draw the planet and spacecraft, and list the order of increasing strength.  Include an explanation for why they are in that order.

8. Answer the question here, draw the masses in their correct order, and explain how you know they should be in that order.

Today you will create a presentation on gravity.  Each slide must be about the answer to the question.  Also, each slide should have an image illustrating the answer.

Use this site for your information.

Slides 1-7 can be found in the “What is Gravity” section.

Slide 1: Title, your name and your partner’s name.

Slide 2: What is gravity?

Slide 3: How strong is gravity compared to other forces?

Slide 4: What two factors determine the strength of the gravitational force?

Slide 5: How is the gravitational force related to distance?

Slide 6: What is the gravitational force equation and what does everything mean?

Slide 7: How does Einstein’s General Relativity explain gravitation?

Information for the following slides can be found in the Small Scale Effects, Large Scale Effects, and The other sections.

Slide 8: What is the strength of gravity on the moon compared to the earth?

Slide 9: How can anything fall without hitting the ground?

Slide 10: What is a black hole?

Slide 11: What is a gravitational wave?

Slide 12: How can you make fake gravity?

Open gravity force lab (http://phet.colorado.edu/simulations/sims.php?sim=Gravity_Force_Lab )

Part I: Force of Gravity

1. What is true about the force of m2 on m1, and the force of m1 on m2 (two things) __________________________________________________________________2. Set both masses equal to 25 kg, and set them both 4 m apart. You can move the masses and rulers.

3. What is the force of gravity? ___________________ Compare the following answers to this answer.
4. Keep the masses 4 m apart, but change one mass to 50 kg.
5. What is the new force of gravity? _____________________
6. How did it change (compared to #4)? ___________________________________
7. Change the 50 kg mass down to 12.5 kg.
8. What is the new force of gravity? _____________________
9. How did it change (compared to #4)? ___________________________________
10. Set both masses back to 25 kg, but move them so they are 8 m apart.
11. What is the new force of gravity? _____________________
12. How did it change (compared to #4)? ___________________________________
13. Given the two masses of 25 kg 8 m apart, how can you change one mass to get back to the answer in #4? _____________________________________________

Open my solar system (http://phet.colorado.edu/simulations/sims.php?sim=My_Solar_System)

Part II: Planetary Motion

I After the simulation loads click Start.

Sketch and describe (your paper) what you see in this simple sun-planet system.

Specifically, what happens to the central object (the Sun)?

Can you explain why the central object moves?

HINT: Is gravitational attraction only the sun pulling on the planet?

Does the planet orbit in a perfect circle? Is the sun at the center?

II Click Stop and then select 3 bodies. Then Start

Sketch a complete cycle (orbit)

Watch the ‘funny’ object closely

What is it doing? Describe and explain.

Could this be the Earth/Moon/Sun system? (Try unchecking Show Traces.)

Is there anything you are uncomfortable with in the simulation? Explain.

Can you explain the difference in the moon’s path when it is on the right

side of the Sun compared to on the left side? (Turn Traces back on.)

III Click Stop and then select 4 bodies. Then Start

Describe what is happening to the inner planet, why.

IV Click Stop and then select 2 bodies again.

Change the mass of the ‘planet’ to 100 units and then Start.

Explain how the motion is different from Part I.

Ever hear of a binary star?

Repeat with both bodies at 200 units of mass.

V Click Stop and then select 3 bodies again.

Change the masses of bodies 2 and 3 to 5 units each and Start.

Watch for several orbits and explain what’s happening.

Open lunar lander (http://phet.colorado.edu/simulations/sims.php?sim=Lunar_Lander)

Part III: Lunar Lander

1. Play the game. Your goal is to have the maximum number of landings before you run out of fuel. Try to keep the landings soft and avoid the boulders.
2. How many landings did you achieve? ___________________________________
3. What was difficult about this game? ____________________________________ __________________________________________________________________

Quiz Practice

Calculating Potential Energy

1. A 50 kg diver stands at the top of a 10m diving board. What is his potential energy?

2. When the diver jumps and is half way down to the water, what is his potential energy?

3. When the diver reaches the water, what is his potential energy?

Calculating Kinetic Energy

1. A 50 kg diver stands at the top of a 10m diving board. What is his kinetic energy?

2. When the diver jumps and is moving at 5 m/s. What is his kinetic energy?

3. When the diver reaches the water, what is his potential energy?

Conservation of Energy

1. A roller coaster at the top of its first hill has 100,000J of potential energy. How much potential energy will it have when it reaches the bottom of the hill?

2. How much Kinetic Energy will the roller coaster have at the bottom of the hill?

3. A 2 kg bowling ball sits at the top of a ramp that is 10m high. If it rolls down the ramp, what will its kinetic energy be?

4. A 2 kg bowling ball sits at the top of a ramp that is 10 m high. What is its potential energy half way down the ramp?

5. Starting from rest, a 2 kg block of wood slides a distance of two meters down a frictionless slope, as shown above. What is the kinetic energy of the block at the bottom of the slope?

Calculating Momentum

1. A 3 kg bowling ball moves down the lane at 3 m/s. Calculate its momentum.

2. A 50 kg skier jumps off a 50 foot jump at 5 m/s. Calculate her momentum.

Elastic Collisions

1. A 3 kg bowling ball moving down the lane at 3 m/s hits another 3 kg bowling ball and comes to a stop. How fast will the second bowling ball travel after it’s been hit?

2. A 3 kg bowling ball moving down the lane at 3 m/s hits a 6 kg bowling ball and comes to a stop. How fast will the second bowling ball travel after it’s been hit?

Inelastic Collisions

1. A 100 kg lineman moving at 3 m/s hits a 50 kg quarterback that is standing still. If the lineman keeps ahold of the quarterback, how fast will they be traveling after the hit?

2. A 50 kg fisherman jumps into a 100 kg boat at a speed of 2 m/s. After the fisherman lands in the boat, how fast does the boat and fisherman travel?

Run the simulation linked here.

1. Pull the bottom of the ramp down to the ground and measure the height of the skateboarder when he is at his highest.  Calculate his potential energy if his mass is 75 kg (PE = mgh).  Turn on the Energy vs. Position or Energy vs. time graph and see if you calculation is right.

2. Run the simulation until he is at the bottom of the ramp.  What is his Kinetic Energy at the bottom (just read it from the graph or use Conservation of energy)?

3. Where did the Kinetic energy in #2 come from?

4. Change the skater to a the girl, measure the girl’s highest point and calculate her potential energy at the highest point.

5. What will be the girl’s kinetic energy at the bottom?

6. Run this simulation.  Draw a picture in your notes and explain how this simulation shows energy conservation?

7. Where is the potential energy the greatest and the least?  Where is the kinetic energy the greatest and the least?

8. Run this simulation. Draw a picture in your notes and explain how this simulation shows energy conservation?

9. Is energy conserved when friction is present?