Class 29.5 Thursday 12/1/22 Warm Up:
Today:
Homework:

Class 29 Wednesday 11/30/22 Warm Up: A 1kg mass is suspended by an ordinary string from the ceiling of a fullyenclosed train car. The car is on a level surface, and the angle shown remains constant. How many of these can we deduce from this information? A) The mass' direction of movement B) The mass' acceleration C) The string tension
Today:
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Class 28.5 Tuesday 11/29/22 Warm Up: None Today:
Homework:

Class 28 Monday 11/28/22 Warm Up: One end of a rope is attached to the Gladys' belt. Gladys is pulling directly downward on the other end. Assuming that the pulley and rope are massless and fictionless, how much downward force must Gladys apply in order to ascend? Gladys weighs 500N. Today:
Homework:

Class 27.5 Friday 11/18/22 Warm Up: What's wrong with this graph of some group's water rocket y position (height) vs. time? How could we fix it? Today:
Homework:

Class 27 Thursday 11/17/22 Warm Up: None  test today
Today:
Homework:

Class 26.5 Wednesday 11/16/22 Warm Up: 1. Draw a series diagrams showing and labeling all of the forces (and their relative magnitudes) acting on the ball in the diagram on the right, based on the following descriptions. A. The ball has not yet been released. It is being accelerated by the thrower's hand. B. Flying through the air, soon before hitting the wall C. The ball has just touched the wall, and the wall is slowing it down, but it has not stopped completely, and it has not begun to bounce back. D. Falling to the floor. E. Sitting motionless after coming to rest 2. Did we really show all of the forces? If not, which ones did we miss?
Today:
Homework:

Class 26 Tuesday 11/15/22 Warm Up: 1. How does NASA simulate weightlessness? 2. You are trying to transfer some drippy sauce across a dinner table using only a drippy spoon. The sauce needs to go from the pot to your plate without dripping. Touching only the spoon, how can you make this happen?
Today:
Homework:

Class 25.5 Monday 11/14/22 Warm Up: The graph on the right shows the current acceleration data for the PocketLab sensor sitting motionless on my desk. The positive Z axis (green) extends "perpendicularly" out of my desk surface. The positive X axis (orange) extends rightward from the sensor. The positive Y (purple) axis extends away from the camera, parallel to the desk surface.
Why are the X and Y axes showing a constant acceleration near 0m/s^2, while the Z axis shows a constant acceleration of around positive 1g?
Today:
Homework:

Warm Up: 1. Some of the rockets did not come apart, so their chutes could not deploy. Speculate on why they didn't separate. 2. How many water bottles are used to launch this game show contestant? Is this for real? Could we launch a student this high? Today:
Homework:

Class 24.5 Thursday 11/10/22 Warm Up: None  get your rocket ready for launching. Today:
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Class 24 Wednesday 11/9/22 Warm Up: What's the best amount of water to put in a water rocket? [Find out, according to Clifford Heath.] How does the amount of water affect force and overall change in velocity? 1. What happens if you don't add any water? 2. What happens if you completely fill the rocket with water? Today:
Homework:

Class 23.5 Tuesday 11/8/22 Warm Up: How can you measure, mark, and cut a nice, big circle (about 65cm in diameter) out of plastic sheeting, in under 10 seconds? Today:
Homework: None 
Class 23 Monday 11/7/22 Warm Up: The diagram on the right shows a water rocket. Mass has been added to the tip of the rocket, and fins have been added to the back (bottom). There is a requisite 10cm long section dedicated to holding foam for protecting the probe. 1. What makes the rocket move upward? 2. Why do fins need to be added to the back of the rocket? How does this work? 3. Why does mass needed to be added to the front of the rocket? How does this work? 4. Aside from stability, what other reason is there for adding mass to the rocket? 5. What's the purpose for the flange at the bottom of the nose cone? [Video link for absent students]
Today:
next Thursday?
Homework: None 
Class
22.5 Friday 11/5/22 Warm Up: On level ground, Tim begins sliding with a velocity of 6m/s. If Tim's slide lasts for 2 seconds, what is the coefficient of kinetic friction between Tim and the slide?
Today:
Homework: 
Class
22 Thursday 11/3/22 Warm Up: The 50kg rower in the photo is accelerating at a rate of 1m/s^{2}. She is pulling against the oars with a force of 100N. Calculate and show all of the forces acting on the rower.
Today:
Homework:

Class
21.5 Wednesday 11/1/22 Warm Up: 1. Explain how a nordic skier can ski forward on level ground with parallel skis (classic style) and without using poles. 2. Downhill skis do not include these innovations, but, as people standing in lift lines often demonstrate, you can still shuffle forward on them (on level ground, without a skating motion or poles). In many situations, you can also shuffle backward, though it may be a little harder. Explain how this works.
Today:
Homework:

Class
21 Tuesday 11/1/22 Warm Up: 1. How fast does chalk fall? Is it faster than a cat?... My spreadsheet answer 2. Sometimes people celebrate special occasions by firing guns into the air. Is this safe? 3. Why don't clouds fall out of the sky? Calculated terminal velocities of various spheres.
Today:
Homework:

Class
20.5 Monday 10/31/22 Warm Up: None Today:
Homework:

Class
20 Friday 10/28/22 Warm Up: None Today:
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Class
19.5 Thursday 10/27/22 Warm Up: I have a length of treated 4"x4" lumber, some large nails, a hammer, and a large rock. How will it feel if I put the rock on my head and then have someone pound nails into the wood on top of the rock?
Today:
Homework:

Class
19 Wednesday 10/26/22 Warm Up: One way to find the center of mass (a.k.a. balance point) of a stick is to support it with two hands and then slowly move those two hands together until they meet under the stick's center of mass. Why does this method work?
Today:
Coming Up:
Homework:

Class
18.5 Tuesday 10/25/22 Warm Up: It is possible to remove a sheet paper from under a dry erase pen without touching or tipping the pen. How can one do this without tipping the pen? Why does the pen usually fall? What kind of pen would work better?
Today:
Homework:

Class
18 Monday 10/24/22 Warm Up: A typical Ydimension acceleration problem... 1. A rappelling rock climber with a mass of 50kg is supported by a rope. If the climber is accelerating downward at a rate of 0.5m/s, what is the tension in the rope? 2. More generally, for the situation where a rope is applying an upward tension (T) to a mass (m) with acceleration a, write an equation relating m, T, and a.
Today:
Homework:

Class
17.5 Friday 10/21/22 Warm Up: What will happen if I poke a knife through a potato, hold both objects in the air with the knife pointing downward, and then hammer the butt of the knife into the potato? Why? What if it's an apple, because I didn't have potatoes? Today:
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Class
17 Thursday 10/20/22 Warm Up: None Today:
Homework:

Class
16.5 Wednesday 10/19/22 Warm Up: There is a heavy object suspended from the ceiling by a string. Another segment of the same string is hanging downward from the object. I am going to pull on the bottom string until one of the two strings breaks. Which string is going to break first? Why? Today:
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Class
16 Tuesday 10/18/22 Warm Up: No warmup today Today:
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Class
15.5 Monday 10/17/22 Warm Up: What do you need to do to get ready for tomorrow's contest? Today:
Upcoming Classes:
Homework:

Class
15 Friday 10/14/22 Warm Up: A boat is following a heading of 56 degrees N of E, and its speed in still water is 1.3 m/s. Find the velocity of the river's current if the boat's actual velocity (relative to the Earth) is 3.2m/s in a direction 17 degrees W of N. Solution... Video explanation
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Upcoming Classes:
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Class
14.5 Thursday 10/13/22 Warm Up: see yesterday?
Today:
Upcoming Classes:
Homework:

Class
14 Wednesday 10/12/22 Warm Up: Final launcher considerations... 1. How are you going to aim your launcher in the horizontal plane? 2. How are you going to aim your launcher in the vertical plane? 3. How are you going to decide on your projectile's initial height? [Remember that you will be given a vertical "launch window," and it is up to you to determine the exact launch height.] 4. How are you going to hold your launcher steady, at the height and angle of your choice? 5. What are you going to do if you take a test shot and it turns out that your distance is off by a large amount?
Today:
Upcoming Classes:
Homework:

Class
13.5 Tuesday 10/11/22 Warm Up: A green hunter and a blue hunter point their guns directly at a monkey. Then they fire simultaneously. Just as the two hunters fire their guns, the monkey slips and freefalls from the treetop. Whose bullet (if either) hits the monkey? Today:
Homework:

Class
13 Thursday 10/6/22 Warm Up: 1. Use your spreadsheet to determine a correct combination of initial velocity and angle in order to hit the target. 2. Use your launcher calibration graph (or table)( to determine the correct launcher setting. **Assume that the surface provided for launching is 0.62m high, so the launcher muzzle can be at any height between 0.645m and 1m.
Today:
Homework:

Class
12.5 Tuesday, 10/4/22 Warm Up: Let's try out the PhET Projectile Motion Simulation and see what it has to offer. What do the various buttons do? The riverboat simulator is also a little bit interesting, but I would change the wording a bit. Can you guess what I would change?
Today:
Homework:

Class
12 Tuesday, 10/4/22 Warm Up: 1. Based on the diagram to the right, provide definitions for precision and accuracy. Which is easier to fix? 2. Can you suggest some ways to improve the precision of a projectile launcher like the ones you are using in this project? 3. How could you improve Accuracy? 4. What are some likely sources of error in attempts to hit the target?
Today:
Homework:

Class
11.5 Monday, 10/3/22 Warm Up: Suppose you want to create a spreadsheet formula that tells you the initial velocity of a projectile following a symmetric flight path. Suppose cell B2 provides the projectile's range and Cell B3 provides the projectile's initial launch angle. Write the formula as you would enter it into a spreadsheet.
Today:
Homework:

Class
11 Friday, 9/30/22 Warm Up: An olympic athlete throws a javelin at an angle of 34 degrees, with respect to the ground. The release point of the javelin is 1.3m above the ground. The javelin travels a horizontal distance of 90 meters and lands after a flight lasting 3.7 seconds. 1. At what angle is the javelin sticking out of the ground at its point of impact? 2. It turns out that the field is not level. How much higher or lower is the field at the point of impact, compared to the field at the point of release? Today:
Homework:

Class
10.5 Thursday, 9/29/22 Warm Up: The diagram on the right shows the symmetric trajectory of a freefalling projectile. Sketch the diagram. 1. What does freefalling mean? 2. Show/label the projectile's overall velocity vector (v), x velocity vector (v_{x}), and y velocity vector (v_{y}) at points A, B (apogee), and C.
Today:
Homework:

Class
10 Wednesday, 9/28/22 Warm Up: None  test retake day Today:
Homework:

Class
9.5 Tuesday, 9/27/22 Warm Up: Suppose you shoot a projectile, horizontally, from the edge of a school tabletop that is 0.95m above the floor. If the projectile hits the floor at a distance of 14 floor tiles from the table... a. What is the projectile's v_{0}? b. How would you find the projectiles' final speed? c. How would you find the angle at which the projectile hits the floor?
Today:
Homework:

Class
9 Monday, 9/26/22 Warm Up: Someone is crossing a river in a boat, navigating by compass in complete darkness. The river flows 30 degrees south of west at a rate of 5m/s. The boat's velocity is 20 degrees west of south, at a rate of 20m/s. How do we calculate the boat's speedometer reading and heading?
Today:
Homework:

Class
8.5 Friday, 9/23/22 Warm Up: Sketch a headtotail diagram for each of the following. Two "component" vectors should add up to the "resultant." The trickiest part is identifying the resultant.
2. A river's 3mph current flows in a direction 15 degrees West of North. A swimmer, whose speed in still water is 2m/s, swims across the river with a heading 35 degrees South of West. What is the swimmer's velocity, relative to the Earth? 3. A superhero steward on an airplane is traveling in a direction 10 degrees East of South, and their speed is 580mph. The plane's velocity is 460mph in a direction 5 degrees West of South. What is the steward's heading and their "speed on a still plane?"
Sketches and answers:  I got rid of number 1. Just ignore solution #1. Today:
Homework:

Class
8 Thursday, 9/22/22 Warm Up: A delivery airplane flying horizontally with a ground speed of 120 m/s releases packages from a height of 4,800 meters. If the packages are not affected by air resistance, how far in advance of the target (in the x dimension) should the packages be released?
Today:
Homework:

Class
7.5 Wednesday, 9/21/22 Warm Up: 1. Suppose the two vectors on the right represent two forces acting on the clam. In what direction will the clam accelerate? How will that acceleration compare to the accelerations we would observe if each force were acting alone? 2. The diagram on the right shows a top view of a train car that is moving at a rate of 2m/s. You are in the car. In which direction and how fast should you walk in order to have the intended velocity shown on the right.
Today:
Homework:

Class
7 Tuesday, 9/20/22 Warm Up: None
Today:
Homework:

Class
6.5 Monday,
9/19/22 Warm Up: Velocity and Acceleration Combinations Matching Quiz. Use this link to take the quiz.
Today:
Wednesday and/or Thursday:
Homework:

Class
6 Friday,
9/16/22 Warm Up: How does a spool car work? Why is the stick necessary?
Today:
Homework:
More Unit 1 Practice (optional!)

Class
5.5 Thursday,
9/15/22 Warm Up: Try problem #58 from p. 26 of the packet (also below). You will see this type of problem again. It doesn't ask for a measurement, but rather a multiplication factor (like 2x, 3x, 1/2x...). 1. What's a good strategy for this type of problem? 2. What's the answer to this one?
The
acceleration due to gravity on the Moon is
about onesixth what it is on Earth. If an object is thrown vertically
upward on the Moon, how many times higher
will it go than it would on Earth, assuming the same initial velocity?
Today:
Homework:

Class
5 Wednesday,
9/14/22 (B5/6 ends at 11:55) Warm Up: 1. Suppose students enter our school at a rate of 54 pounds/sec (pounds of student). After they enter, they lie down, headtotoe, forming a line whose length is the sum of their heights. Since an average 16 year old student's weight:height ratio is about 2.07 lb/in (and assuming these are all average students with that ratio), how many days will it take them to form a line 3 miles long? 2. How does dimensional analysis work? On what basic mathematical premise is it based? 3. This problem (#1) is fine for dimensional analysis practice, but it's not actually solvable given the information provided. Explain.
Today:
Coming Up:
Homework:

Class
4.5 Tuesday,
9/13/22 Warm Up: What would a graph of X velocity vs time look like for a pendulum that is swinging back and forth (left to right and back). Assume that it starts from the far left of its swing.
Today:
Homework:

Class
4 Monday,
9/12/22 Warm Up: Suppose a dart is thrown rightward across a room, finally embedding in a dart board. Sketch a graph of the dart's x acceleration (horizontal acceleration only) from the time it begins to move to the time at which it stops.
Today:
Homework:

Class
3.5 Friday,
9/9/22 Warm Up: Consider the case of this ball. At t = 0s, the ball is freefalling directly upward at a height o 10m, with a speed of 20m/s. Sketch graphs of the ball's position, velocity, and acceleration (vs. time) over the next 4 seconds. [For simplicity, use g =10m/s^{2} instead of g = 9.8m/s^{2}]
Today:
Homework:

Class
3 Thursday,
9/8/22 Warm Up: The top box on the right shows the 6 formulas that you can use to solve any kinematics problem in this unit. The bottom box lists all of the variables that appear in the formulas. [Note that I have left out x and x_{0}.] 1. Try to create an interesting physics problem, either by starting with a formula (or two) that will help solve the problem, or by selecting some variables as "givens." 2. Solve your problem.
Today:
Homework:

Class
2.5 Wednesday,
9/7/22 Warm Up: Match each position vs. time graph with the correct velocity and acceleration graph.Today:
Homework:

Class
2 Tuesday,
9/6/22 Warm Up: 1. Assuming that the man in the picture is 2m tall, and the frame rate of the camera was the usual 30 frames per second, what was the approximate maximum speed of the object? 2. Based on your answers, do you think the assumption of 30 frames per second was too low, too high, or about right? Today:
Homework:

Class
1.5 Friday,
9/2/22 Warm Up: Use the velocity vs time graph on the right to sketch the shape of a corresponding position vs time graph. [Assume that motion away from the sensor is positive, and motion toward the sensor is negative.] Today:
Optional Reading  Online Textbook: Homework:

Class 1:
Thursday,
9/1/21 Warm Up: Suppose you're involved in a 2 lap race. If you want your overall average speed to be twice as fast as your speed for the first lap, how much faster do you have to go during the 2nd lap? [To calculate average speed you can use rate = distance / time] Today:
Optional Online Textbook Reading: Homework:

Class
0.5: Wednesday,
8/31/22 Physics 200: Mr. Stapleton Warm Up: Spin one of the "sprotating cylinders" by pressing one end until it squirts out from under your finger. Try pressing the other end. When the cylinder is spinning, why do you only see the symbol that you press? Today:
Links: Online Textbook Reading: Homework: None 