PASCO ME-9341 INTRODUCTORY ROTATIONAL APPARATUS - Manual (Page 30)

Introductory Rotational Apparatus 012-03051F
26
average
Object Mass (g) Force (N) R (m) alpha (rad/s/s)
Base Plate 25.5700 0.2506 0.015 0.4111
46.3500 0.4542 0.015 0.8646
87.2300 0.8549 0.015 1.6976
117.4100 1.1506 0.015 2.3157
157.7600 1.5460 0.015 3.1756
191.7200 1.8789 0.015 3.8850
B.P. + ring 25.5700 0.2506 0.015 0.2858
B.P. + disk 25.5700 0.2506 0.015 0.1917
B.P. + bar 25.5700 0.2506 0.015 0.2694
B.P. 25.5700 0.2506 0.015 0.4472
25.5700 0.2506 0.020 0.6253
25.5700 0.2506 0.025 0.7704
Notes – on Analysis
The acceleration is directly proportional to the radius for a
constant force.
The acceleration is directly proportional to the force for a
constant radius.
Increasing the mass by adding another disk increased the
rotational inertia and decreased the acceleration.
Ranking the three objects in increasing order of inertia would
give: ring, bar, then disk. This is misleading, because for
objects of the same mass and radius the ring would have the
highest inertia. The lower inertia of the ring is due to its
smaller radius, not its shape.
Notes
The assumption that the force on the turntable equals mg is valid
only for small masses and acceleratons. Using larger masses will
lessen your accuracy in this experiment. If the masses used are too
small, then the friction in the device may be proportionally large
enough that it causes errors as well. Generally, keep the falling mass
between about 20 and 200 grams.
With the assumption mentioned, this lab is essentially identical to
experiment 1.
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0
0.5
1
1.5
2
2.5
3
3.5
4
0 20 40 60 80 100 120 140 160 180 200
angular acceleration
mass (g)
Acceleration vs. Mass
radius = 1.5 cm
Acceleration vs. Mass
radius = 1.5 cm
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0
0.2
0.4
0.6
0.8
1
0 0.005 0.01 0.015 0.02 0.025 0.03
angular acceleration
radius (cm)
Angular Acceleration v. Radius
mass = 25.57g
Angular Acceleration v. Radius
mass = 25.57g