STUDY GUIDE
FOR SECTION IV
The course and, consequently, the tests emphasize problem solving. In order
to solve problems one needs to master the underlying concepts and principles.
This guide points out some of the basic terms, concepts, principles or laws. In
addition, please review sample problems in you notes and do the homework
assigned on WileyPlus. You have to understand and use the physics principles when
you do problems. The bad habit of plugging in numbers into formulas without understanding the
underlying physics concepts and principles leads to disasters not only on
tests but also in real life.
Ch. 8 &9 :
Rotational motion, Rolling motion , Torque and Angular
Momentum
Visit this
website. It shows the parallel between linear and angular
motion as well as the derivation of moments of inertia for some common geometric
objects such as a solid sphere,-
cylinder etc.
- Be able to use the equations of motion for
constant angular acceleration listed in table 8-1 (Page 221).
-
Be able to relate linear and angular variables (Table 8-1 and Table 9-2)
- Be able to calculate the moment of inertia
for a system of particles or rigid bodies rotating around an axis passing
through their CM or any axis parallel to it.
- Be familiar with Table
9-1 and be able to
use the parallel axis theorem to convert Icm to
Iparallel . Be able
to wisely use the information in Table 9-1 and/or the above website along with the parallel
axis theorem. You will be given this info for use in your test.
-
Be able to calculate rotational Kinetic Energy.
- Be
able to calculate torque ( T =r x F) angular
momentum (L = r x p and/or L = Iω) as a vector products and figure out directions
of of T and L using the right hand rule.
- Be
familiar with Newton's 2nd law for rotation.
- Be
able to relate torque and angular momentum as well as torque and angular
acceleration
- Be
able to state and apply the conservation of L in solving
problems and explain: Why a spinning wheel does not fall; Why a
gyroscope or a spinning top maintains its direction.; Why skaters spin
faster when their arms pulled in and slow ere when their arms are stretched. Why pulsars spin faster than stars. Why a
helicopter needs a rear rotor etc.
- Be
able to explain that Kepler's 2nd Law of planetary motion (The
Law of Equal Areas) is a consequence of the conservation of L. See page 265.
- Be
able to explain and do calculations related to the demo with the rotating
stool and weights that will be done in class.
- Be able to use conservation of energy when both transitional and
rotational kinetic energies are present. See examples in Chapters 8 & 9
examples in your notes.
- Review your last three labs. Archimedes's principle, Standing waves in
stretched strings and air columns.
- Be
able to calculate the speed of sound using the three methods used in the las
lab.
Please study section 11.6 -Archimedes' principle and sections
16.1,16.2,16.3 , 17.5 and
17.6- on sound waves. and waves on stretched strings. This is
related to the last two experiment in PHYS 201L
You may visit the sites below if you want to understand Angular Momentum
http://www.youtube.com/watch?v=yAWLLo5cyfE
Conservation of Anglualr
Momentum Li =Lf