Purpose: This lab will verify how the centripetal force on a rotating body is affected by the following variables: frequency, speed, mass, and radius of a rotating object.
● 2 rubber stoppers
● 28 steel washers
● reinforced ceramic tube
● 1.5 m of thread or string
● metre stick
● stop watch
Remember that a proper scientific method requires identifying the following for each case of the investigation: → Independent Variable
→ Dependent Variable
→ Controlled Variables
PART A - Centripetal Force vs Frequency
1. Set up apparatus as illustrated above. Measure 1.0 meter of string from the rubber stopper to the tube (held vertically) using the metre stick. Attach a piece of tape on the string about 1 cm below the bottom of the tube (see diagram pg. 152). This will act as a reference mark.
2. Place 12 washers on the end of the string (using the paper clip).
3. While holding the bottom stack of washers, whirl the rubber stopper in a horizontal circle above your head. Carefully adjust the speed of rotation until you feel very little tension on the string suspending the washers. Let go of the stack of washers and maintain the rotation rate so that the reference tape on the string remains stationary about 1 cm below the tube. Have a lab partner determine the time for 20 complete rotations.
4. Set up a chart as illustrated below.
| | | | |
|Number of Washers |Number of Rotations |Time |Frequency |
|(Force Units) | ...