PASCO ME-8950A COMPLETE ROTATIONAL SYSTEM - Manual (Page 23)

012-05293F Complete Rotational System
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Experiment 3: Centripetal Force
EQUIPMENT NEEDED
- Centripetal Force Accessory (ME-8952) - Rotating Platform (ME-8951)
- Stopwatch - Balance
- Graph paper (2 sheets) - Mass and Hanger Set
- String
Purpose
The purpose of this experiment is to study the effects of varying the mass of the object, the radius of
the circle, and the centripetal force on an object rotating in a circular path.
Theory
When an object of mass m, attached to a string of length r, is rotated in a horizontal circle, the centripetal
force on the mass is given by:
where v is the tangential velocity and ω is the angular speed (v = r ω). To measure the velocity, the
time for one rotation (the period, T) is measured. Then:
and the centripetal force is given by:
Setup
Level the "A" base and rotating platform as described in the ME-8951 assembly section in the
introduction to this manual.
Procedure
Part I: Vary Radius (constant force and mass)
1. The centripetal force and the mass of the hanging object will be held constant for this part of the
experiment. Weigh the object and record its mass in Table 3.1. Hang the object from the side post
and connect the string from the spring to the object. The string must pass under the pulley on the
center post. See Figure 3.1.
F
mv
2
r
--------- mr ω 2
= =
v
2 πr
T
--------- =
F
4 π
2
mr
T
2
---------------- =