Experiment: Determining angular velocity using a camera

Topics covered:

- Rotational motion

- Uniform motion

- Accelerated motion

- Angular velocity

- Velocity and acceleration vectors

Principles and objectives:

Study uniform circular motion using Data Acquisition in the generalist physics and chemistry Scientific Workshop.

Place a contrasting mark on one end of the moving arm.

Rotate the arm and capture the video.

1.1- Positions (x; y) as a function of time

The processing of the recording, using the video tab of the PC Scientific Workshop, allows for the determination of the positions x(t)

and y(t) of the contrasting object manually or automatically.

1.2- Velocities and accelerations as a function of positions on 1 lap

Using the portion tool of the Scientific Workshop, isolate all points corresponding to a complete lap. In the

graphical area, plot the coordinates x as a function of y, a simple right-click on the graph then gives access

to the vector representation of the velocity and acceleration at the selected points. The velocity and acceleration vectors

have constant magnitudes along a lap: this shows the uniform nature of the motion

1.3- Angular velocity

Using the angle tool integrated in the video processing tab, measure the angles and determine the angular velocity as a function

of time. Highlight that it is constant in the case of uniform circular motion. Note:

angular velocity can also be calculated from the positions x(t) and y(t) in the spreadsheet.

- Dynamic rotation model (ref 322169) - Fast camera 2 + Cinéris (ref 577017) - 250m cord (ref 323004) - Set of hook masses (ref 703016) - Modumontage stand (ref 701293) - Polynux nut (ref 703452)