PURPOSE:
To expose the student to new equipment and lab procedures. And to calculate the torque produced in a simple lever setup.

INTRODUCTION:
In physics, torque (or often called a moment) can informally be thought of as "rotational force" or "angular force" which causes a change in rotational motion. This force is defined by linear force multiplied by a radius. The force in this experiment is produced by the mass of a brass and unknown weight and gravity:

F = m g

The radius, mentioned above, is the length of the "lever arm" from the pivot point to the mass. In the picture below, the right brass weight has a lever arm of 0.30 m, the left brass weight has a lever arm of 0.10 m and the gray weight has one of about 0.485 m. The equation for torque is:

torque = F r

In our picture, the torque on the right equals the total torque on the left and thus the meter stick is level and nonmoving. The total torque for the left side is the sum of the torques produced by the brass and gray weight. During this lab you will determine the mass of an unknown weight, lever arm lengths and torques produced for three separate examples.

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The lab will be conducted on a meter stick with its pivot point at the 50 cm mark. Known brass weights and an unknown weight will provide the masses that create the torque on each side of the meter stick.

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If you get into trouble and perform some procedure that causes the lab to fail(lab equipment will no longer operate), you can press the "Reset" button and the simulation will return to the starting position.

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PROCEDURE:

1) You can adjust the background shading by clicking on the "Special" button to the right and selecting "Background". Click on the "Special" button and select "Print Blank Report" to obtain a web page that can be printed and used as a lab report. (the program will not be interrupted)

Room 1

2) Record the length(in m) of the lever arm(from the pivot point to the object) of the brass weight. Drag the unknown gray weight until the meter stick is level and motionless. Record the lever arm(m) of the unknown mass. The mass of the brass weight has already been entered into the data sheet for you. See the "View Data and Hints" section under the "Special" button. Move to the next room.

Room 2

3) Record the length(m) of the lever arm of the right brass weight. Record the length(m) of the lever arm of the left brass weight. Drag the unknown gray weight until the meter stick is level and motionless. Record the lever arm(m) of the unknown mass. The mass of the brass weights have already been entered into the data sheet for you. See the "View Data and Hints" section under the "Special" button. Move to the next room.

Room 3

4) Record the length(m) of the lever arm of the brass weight. Drag the unknown gray weight until the meter stick is level and motionless. Record the lever arm(m) of the unknown mass. The mass of the brass weight has already been entered into the data sheet for you. The length of the meter stick to the right of the pivot point, and to the left of the pivot point have also been entered into the data sheet for you. See the "View Data and Hints" section under the "Special" button.

5) Calculate the requested values asked for on the lab sheet and any given by your teacher. Select "File Report" to send a copy to be viewed by your teacher.