LAB 10.docx - Usama Zia Lab 9a1: Moment of Inertia and...

Usama Zia
Lab 9a1: Moment of Inertia and Energy in Rotational Motion
PHYS 111A-010
Date of Experiment: 6/17/21
Date of Report: 6/20/21
Instructor: Ion Cohanoschi
Introduction:
Objectives:
1. To explore the rotational motion of rigid bodies with respect to angular position and
angular velocity at a constant angular acceleration;
2. To evaluate the relation of those angular quantities to the linear position and linear
velocity in a system with a bound motion including translational and rotational motion;
3. To experimentally determine the moment of inertia of an object and compare to the
calculated one; and
4. To demonstrate the conservation of energy in a system involving a rotational motion.
Theoretical Background:
The angular displacement, from time to time
The average angular velocity
The instantaneous angular velocity
The average angular acceleration
The instantaneous angular acceleration is
The rotational inertia of solid disk rotating access through its center of mass
The rotational inertia of a ring rotating through its center of mass
Total rotational kinetic energy

Traveling distance of hanging mass represents its relative height
Procedure:
Main goal of this lab is to experimentally determine the moment of inertia of an object with help
of the law of conservation of energy and compare it to theoretically calculated one.
Part I: Measure the physical quantities of objects used in this experiment.
The following measurements are basically necessary in order to calculate the theoretical moment
of inertia of
each object and to relate the linear velocity of the hanging mass to the angular velocity of the
rotating body.
1. Measure the masses of a disk, a ring, a square mass, a mass hanger, and a given weight (see
Figure 7).
2. Measure the radius of the disk and the inner and outer radii of the ring (refer to Figure 4).
3. Measure the radius of the rim of the 2nd pulley from the top of the step‐pulley where the string
is wound (refer to Figure 3).
Part II. Theoretical determination of the moment of inertia of an object
1. Calculate the rotational inertia when each of two point masses (the 300 g‐square mass) is
positioned equally apart from the rotational axis by d distance. The d value will be given by your
instructor.
2. Calculate the rotational inertial of the disk when it rotates around its center of mass (refer to
Figure 5(A)).
3. Calculate the rotational inertial of the disk when it rotates at axis of rotation off its center of
mass by d
distance (refer to Figure 5 (B)). The d value will be given by your instructor. .