When my school switched to block schedule I lost about 24 hours of class time. I decided to do less example problems to free up time for labs and activities. I created these videos for the students that needed to see more examples. I made them for students taking AP Physics Mechanics C as a first year class. Because of this, many would be applicable for an AP Physics 1 or honors physics class. Some were made to support workshops and student study sessions. I also posted videos of class notes for absent students. I include a downloadable PowerPoint file whenever possible so you can use them to make your own videos or use them in class. Feel free to edit them and there is no need to attribute me. The equations may not be editable in your version of PowerPoint. You can install an older version if you want to edit them. I always keep a version of Office 2008 for this and other compatibility issues.
A basic introduction to freefall. The position and velocity of a dropped object is found at 1, 2, and 3 seconds. Several problems are then suggested with answers given.
Example problem in constant acceleration kinematics with two objects that may or may not collide. Shows the advantage of a systematic approach rather than a guess and check method that some students start out using. One of my few whiteboard videos, you can see why!
Example adding 2 vectors together using components. Shows how you can use a PhET simulation to add a new dimension to your videos. I am using the Vector Addition sim and a graphics tablet with a screen overwriting app called Ink2Go.
A quick introduction to projectile motion. An object is projected horizontally off a 45 m cliff. Its position and velocity are determined at t=1, 2 and 3 s. An intro movie shows 2 women going off a high dive, one walks off, one runs off, they hit the water at the same time.
Find the horizontal distance a projectile will land when projected in a horizontal direction. Surprise ending shows why you should always calculate before you leap.
How to determine the range of a projectile. Shows how you can use a PhET simulation to add a new dimension to your videos. I am using the Projectile Motion sim and a graphics tablet with a screen overwriting app called Ink2Go.
How to determine the maximum height of a projectile. Shows how you can use a PhET simulation to add a new dimension to your videos. I am using the Projectile Motion sim and a graphics tablet with a screen overwriting app called Ink2Go.
How to determine the range of a projectile shot from a cliff. Shows how you can use a PhET simulation to add a new dimension to your videos. I am using the Projectile Motion sim and a graphics tablet with a screen overwriting app called Ink2Go.
An introduction to Newton’s Third Law and how to apply it to typical test questions.
Example problem to help students see tension is not sum of forces pulling in each direction. Slides found in above slide set at the end, Newton3-copy.pptx
An example problem solving for the normal force and acceleration of a box dragged by a rope that is at an angle to the horizontal.
An example using Newton’s Second Law to solve a problem with an object being pushed up a ramp.
An example problem using Newton’s Second Law to solve a problem with a system of 2 blocks. Contrast with energy method found below and here: https://youtu.be/Yqu2xtHDGCg
Clicker questions on the physics of elevators including how to determine the normal force for various accelerations.
Physics of Elevators including how to determine the normal force for various accelerations. Slides are in file for previous video, Elevators-Part 1.
Determine the coefficient of static friction between a ramp and an object by tilting it until the object just starts to slide.
An example of using Hooke’s Law to determine the spring constant when the length of the spring is unknown. A second example to determine an unknown mass is included. Shows how you can use a PhET simulation to add a new dimension to your videos. I am using the older version of the Masses and Springs sim and a graphics tablet with a screen overwriting app called Ink2Go.
An introductory look at the physics of springs and Hooke’s Law. The equation for elastic potential energy is derived.
An example problem with a spring accelerating a cart down a frictionless track. Predict the speed at some point. At the end students are asked if they can predict the position given the speed.
An example calculating the work done on an object that is changing height and speed. Work is the sum of the change in potential energy plus the change in kinetic energy.
An example showing how to determine the work done by a force that varies in a linear way. Three methods are shown, using average force, getting area of a shape, and getting area of a square on the grid and multiplying by the number of squares
Physics analysis of bungee jump scene from the James Bond film, Goldeneye. What is the tension in the bungee and Bond’s arms at the end of the stretch?
Continued physics analysis of bungee jump scene from the James Bond film, Goldeneye. What is Bond’s maximum speed and how did Q figure out how long to make the bungee cord? Slides are in the set at the bottom of the Part 1 Bungee video.
An example conservation of energy problem with a modified Atwood machine. The final speed of the system is determined. The acceleration can then be calculated using kinematics. Compare to using Newton’s Laws to solve by watching Free Body Diagram 3 video above, also here: http://youtu.be/HbYfKnnPFUc
An harder example problem where friction does work on a system. First there is friction on an incline, then friction on a horizontal surface.
Clicker question introduction to the concept of impulse and the impulse/change in momentum equation. Several examples are worked out in an interactive way. Impulse as area under the curve and the integral of Fdt are introduced.
An example conservation of momentum problem in 2 dimensions. An object explodes into 3 pieces, find the magnitude and direction of the velocity of the third piece.
I go through an example of a 1 dimensional elastic collision using conservation of momentum and energy and then using the center of mass frame of reference technique using some cool video.
Using a roller coaster as an analogy for the often abstract potential energy function problems that are part of the AP Physics Mechanics C curriculum as well as any college engineering physics class.
An introduction to how to determine the linear and angular speed of an object moving in a circle. For some reason I used to use “tau” as the symbol for period. The slide set below has been changed to use “T” for period.
I estimate the acceleration of the occupants of the 2001: A Space Odyssey space station.
An example problem of a bucket spinning in a vertical circle with Rhino the hamster inside. What is the minimum speed so Rhino stays in the bucket? What is the Normal force on Rhino at the bottom? There is a typo in the video, should be m = 0.08 kg at the end, answer is correct. It is fixed in the slides below.
An example conical pendulum problem. Given the angle, length, and mass, find the period. The correct answer for the period is 2.38 s, NOT 0.9 s. This is fixed in the slides below. The symbol for period in the video “tau” has been changed to “T” in the slides.
An example problem of circular motion in a vertical plane with a Ferris Wheel. Find the Normal force on the rider at the top and the bottom.
An circular motion example problem of the amusement park ride called the rotor. Solve for the minimum coefficient of friction so the riders don’t slip.
An example problem of a car going around an unbanked turn. Find the minimum coefficient of friction so the car doesn’t slide.
An example problem of a car on a banked turn, neglecting friction. Find the speed the car must travel so it doesn’t slip. The slides below explore what happens if there is friction and the car is going too fast and too slow.
A brief review of kinematics with constant acceleration is followed by an introduction to the equations of rotational kinematics with constant angular acceleration. Example problems using a turntable and LP record are performed with some opportunity for student interaction. This is similar to the in-class lecture and is meant for review or absent students.
An introductory lecture on Newton’s Laws for Rotation. The angular acceleration for several systems are determined using free body diagrams. This is similar to what we did in class and is meant for review and students who were absent. There is some duplication with this and the following 3 videos and slide sets.
Newton’s Second Law for rotation is introduced and used for several example problems. Rolling is introduced and the acceleration of rolling objects is determined. Some material is a repeat from the previous video and slide set.
An example where the acceleration of an object rolling down a ramp is determined. The point of contact is used to sum the torques. Slide found in NSLforRotation slides above.
An example where the acceleration of an object rolling down a ramp is determined. The center of the cylinder is used to sum the torques. Slide found in NSLforRotation slides above.
The derivation of the rotational inertia of a thin rod about any point using parallel axis theorem and by integration. Slide found in NSLforRotation slides above.
Introduction to center of mass and how to find it for systems of 2 particles and for “n” particles. The center of mass equation is derived.
Two examples of statics problems where the torque from the weight of an object and locating it at the center of mass is important. The first example determines the mass of a meter stick by balancing a known mass on it. The second is a hinged beam at an angle to the horizontal held by a cable. Slides in CenterofMass slides above.
The beam from the Statics Examples screencast is free to rotate after the cable is cut. Use Newton’s Law of rotation to find the initial angular acceleration. Use energy conservation to determine the angular velocity of the beam when it is in the horizontal position.
The equations for x, v, and accel as a function of time in simple harmonic motion are derived from physics principles and the kinematic relationships between them. No calculus is used. A practice problem and solution are given at the conclusion.
Review of SHM of a Spring/Mass system. Helps to have this comparison as new SHM systems are discussed. Not in the video but the last slide in the set below uses calculus to solve the differential equation for SHM.
A review of torsion pendulums including how to derive the period equation, plus an example problem. Slides are in SHMExamples above.
SHM Review with a simple pendulum. Uses a linear motion approach. Helps to compare it to a rotational dynamics approach used with the physical pendulum below. Slides are in SHMExamples above.
The characteristics of a physical pendulum and how to derive the equation for the period. Slides are in SHMExamples above.
Find how far to drill a hole from the center of a meter stick so it pivots with a 2.5 s period. Sharp-eyed viewers noticed the constant term in the final quadratic should be 0.0833. Slides are in SHMExamples above and the typo is fixed in them.
Shows that it is possible for both solutions to be valid for a problem that has 2 solutions from the quadratic. This is a live demonstration of the results found in the SHM Physical Pendulum Example video above.
An example problem with a pendulum. Find the amplitude, max v, Max a, period, frequency, angular frequency, and max tension. Energy and Newton’s Laws are used and contrasted with using the equations from SHM for a simple pendulum. There is a typo in the equation for period but the answer is correct. The slides are corrected.
The force of gravity on an astronaut is determined when she is on the surface, inside a deep hole, and inside a tunnel through the planet at any distance R’ from the center. The density and volume are used to calculate the relevant mass of the planet using Newton’s Shell Theorem. The astronaut jumps in the tunnel and her motion is described. The equation for the period of the motion is derived and used to calculate the period.
An example problem where 2 stars are released from rest, predict their velocities when they are some final separation using conservation of energy. The problem is simulated using the PhET “My Solar System” program that uses G = 10,000. Shows how you can use a PhET simulation to add a new dimension to your videos. I am using a graphics tablet with a screen overwriting app called Ink2Go.
The circular orbital motion of 2 unequal mass stars about their center of mass is determined. The problem is simulated using the PhET “My Solar System” program that uses G = 10,000. Shows how you can use a PhET simulation to add a new dimension to your videos. I am using a graphics tablet with a screen overwriting app called Ink2Go.
Example problem solving for the distance you would fall in one lifetime (80 years). Assumes Earth’s gravity is only influence. Not part of the AP Physics curriculum other than use of the orbital period equation. Inspired by this Non Sequitur cartoon: https://www.gocomics.com/nonsequitur/…
A summary of the derivative and integral relationships found in AP Physics Mechanics C.
An example of how to determine the differential equation for v(t) for an object experiencing a velocity dependent force. Uses the “guess and check” method that is easier for non-calculus students to follow because it is mostly algebra. Slide in CalculusPhysicsSummary slides above.
Solving the differential equation for free fall with air resistance using separation of variables.
The force of the chain hitting the ground as a function of time is solved for, modeled, and then measured experimentally. Details about doing this in a physics lab and the Blockly code for modeling the equation are shared.