PASCO ME-9341 INTRODUCTORY ROTATIONAL APPARATUS - Manual (Page 20)

16
Introductory Rotational Apparatus 012-03051F
Name: Date: Group:
➆ Now let the mass hang with the thread fully extended. Measure the distance between the mass
and the floor, and record this value as h
2
.
➇ Repeat your measurements at least three times, keeping h
1
constant. Repeat more times if your
data shows any inconsistencies between trials.
➈ Repeat steps 4-9, but change the mass to 100, 150, and then 200 grams.
➉ Further experimentation can be done with different spindles of the step pulleys and with
different numbers of platters. Follow your instructor's direction.
Analysis
For each trial, calculate GPE ( mg h ), the gravitational potential energy lost by the falling
mass. Also calculate RKE ( 1/2 I
ω
2
max
), the rotational kinetic energy gained by the rotating
disk. (For your disk, the value for I is 7.75 x 10 -3 kgm 2 .) Was energy conserved?
Part of the gravitational energy also went into the kinetic energy, KE (1/2 mv 2) , of the falling
mass. To determine this quantity, calculate v
max
= r
ω
max
, where r is the radius of the step
pulley over which the thread passes. Calculate the translational kinetic energy and add it to the
rotational kinetic energy. Is energy conserved now?
Report
Your report should include Purpose, Procedure, Data, and Discussion.
Table 3.1
Calculations
GPE RKE KE RKE + KE
Data
Trial r m h
1
h
2
ω
max