Pedagogy in Action > Library > Using Direct Measurement Videos to Teach Physics > Video Library > Forces and Motion

# Forces and Motion

Videos shown here contain grids, rulers, frame counters and other overlays that allow students to make measurements directly from the videos. Students can use this data to answer questions and solve problems. For each video, sample questions are shown, and in some cases, sample lesson plan ideas.
To analyze a video frame-by-frame, you will want to download the video file to your computer and open it using QuickTime. Clicking on the links shown here will allow you to view the video in your browser, but you may not be able to view the video frame-by-frame.

#### Puck Slides on Smooth Surface

This clip shows a cart that slides a small puck along a smooth surface. There are many physics concepts that can be observed in this video, including the relationship between the kinetic energy of the puck and the work done my the force of friction as the puck slides.

Download the QuickTime files: Direct Measurement Video of a puck sliding (slow) (Quicktime Video 7.1MB Jul15 13) here and Direct Measurement Video of a puck sliding (fast) (Quicktime Video 6.3MB Nov8 13)

Sample question: What is the relationship between the speed of the cart and the distance the puck slides?

#### Hockey Slap Shot

This clip shows a slow-motion video of a hockey slap shot. The carbon fiber stick bends as the force of the puck on the stick increases.

Download the QuickTime file: Direct Measurement Video of a Hockey Slap Shot (Quicktime Video 2.4MB Jul15 13) here.

Sample question: What is the average force by the stick on the puck during the time they are in contact?

#### Rotating Fish Tank

This clip shows a fish tank filled with water rotating at about one rotation per second. The surface of the water forms a paraboliod – a 3-dimensional parabolic surface. In the second part, fish are placed in the tank to observe the effect of the rotation.The fish were unharmed by this demonstration.

Sample question: Can you derive the equation for the parabola that passes through the axis of rotation of the tank? Does the shape shown in the video match your derived equation?

#### Fire extinguisher powered rocket cart accelerates across stage

Screen shot from a Video of a student riding a rocket powered cart (Quicktime Video 2.1MB Jul7 12)
This clip shows a student riding a cart powered by a carbon-dioxide fire extinguisher modified to act as a rocket.

Sample question: Determine the average acceleration of the cart.

#### Cart accelerated by mass hanging on a string

This clip shows a low-friction cart on a horizontal track. A mass hanging from a string attached to the cart causes the cart to accelerate.

Download the Quicktime file: cart accelerated by mass on a string (Quicktime Video 7.7MB Nov11 12) here.

Sample question: Predict the acceleration of the cart using the information provided in the video. Use the video to find the percent difference between your predicted acceleration and the acceleration shown in the video.

#### Forces on an object on a ramp part 1: parallel to the ramp

This clip shows a low-friction cart held in place on a ramp. As the ramp angle increases, the force sensor shows the increase in string tension.

Download the Quicktime file: Forces on a ramp part 1: parallel to ramp (Quicktime Video 1.7MB Nov11 12) here.

Sample question: Predict the string tension when the ramp angle is 18 degrees. Use the video to find the force scale reading when the ramp angle is 18 degrees. What is the percent difference between your prediction and the scale reading shown on the video?

#### Forces on an object on a ramp part 2: perpendicular to the ramp

This clip shows a student on a bathroom scale on a ramp. As the ramp angle increases, the scale reading decreases.

Sample question: How much does the student weigh? Predict the scale reading when the ramp angle is 17 degrees. Use the video to find the scale reading when the ramp angle is 17 degrees. What is the percent difference between your prediction and the scale reading?

#### Low-Friction Cart Rolls Down a Ramp

Screen shot from a Cart rolls down ramp video (shallow) (Quicktime Video 733kB Feb14 14)
This clip shows a low friction cart rolling down a ramp in a physics lab. You can see the video by clicking the link at right and view the video in your browser. There are two additional versions of this video:

video of cart rolling down ramp 2 (Quicktime Video 175kB Jul7 12)
video of cart rolling down ramp 3 (Quicktime Video 162kB Jul7 12)

Sample question: Use the ramp angle to determine the acceleration for a frictionless object sliding on the ramp. Determine the acceleration of the cart on the ramp. Compare these values. Are they the same? Why or why not?

Sample activity: Direct Measurement Video of a Cart Rolling Down a Ramp

#### Conical Pendulum (aka: airplane on a string)

This clip shows a toy airplane on a string moving in a circle.

Download the Quicktime file: Direct Measurement Video of Airplane on a String (Quicktime Video 4.1MB Feb21 13) here.

Sample question: What is the mass of the toy airplane?

Sample question: What is the speed of the toy airplane?

#### Looping Roller Coaster

This clip shows a looping roller coaster recorded using a high-resolution high-speed camera.

Download the Quicktime file: video of corkscrew loop (Quicktime Video 14.2MB Mar10 14) here.

Sample question: Determine the ratio of centripetal force on the third car in the train when it is at the top of the loop compared to the bottom.

#### Steel Ball in a Rotating Glass Bowl

This clip shows a steel ball bearing in a glass bowl that is spinning

Download the Quicktime file: Video of a steel ball in a spinning glass bowl (Quicktime Video 1.9MB Aug7 12) here.

Sample question: Determine the radius of the path the ball follows.

#### Toyota Prius slides across ice rink

Screen shot from a video of a car sliding across an ice rink (Quicktime Video 7.2MB Jun23 14)
This clip shows a Toyota Prius sliding to rest across an ice rink.

Sample question: Determine the effective coefficient of friction between the car tires and the ice.

#### Runner wearing rubber soles shoes slides across ice rink

Screen shot from a Video of a person sliding across an ice rink (Quicktime Video 5.4MB Jun23 14)
This clip shows a person wearing rubber soled shoes sliding to rest across an ice rink.

Sample question: Determine the coefficient of friction between the runner's shoes and the ice.

#### Brass cylinder slides across lab table

Screen shot from a video of a metal cylinder sliding across a table (Quicktime Video 107kB Jul7 12)
This clip shows a 1 kg brass cylinder sliding to rest across a lab table.

Sample question 1: Determine the coefficient of friction between the cylinder and the table.

Sample question 2: Determine the increase in thermal energy of the table and cylinder as the cylinder slides from the 0 cm mark, until it comes to rest.