The Study of Minerals
The ability to identify minerals using the simplest of techniques is a necessity for the Earth scientist, especially those scientists working in the field. In this exercise you will become familiar with the common physical properties
1
Hardness
Less than 2.5
Description A mineral that can be scratched by your fingernail (hardness = 2.5). A mineral that cannot be scratched by your fingernail (hardness = 2.5), and cannot scratch glass (hardness = 5.5). A mineral that scratches glass (ha
Common Rocks
|o an Earth scientist, rocks represent much " more than usable substances. They are the materials of the Earth; understanding their origin and how they change allows us to begin to un derstand Earth and its processes. It is often said that "t
EAS 375
Fall 2010
Lecture questions - Energy
1. There have been a series of energy crises in the past. What were the causes
of these crises?
-1st: Diminishing availability of wood in England in the 12 century.
-alternative was coal.
-2nd: Decline in sperm
Lab on Hydrology, Running Water, Erosion, and Sediment Transport
In this lab you are going to go through a basic outline of information about hydrology. As part of this activity is The Virtual River. I want you to gain an understanding of hydrology and ho
Count # of equations and unknown (should be equal!)
T sin = Fc
T cos = Fg
Fg = mg
5=5
2
q
Fc = k 2
d
d/2
sin =
l
eliminate d
74
Thursday, August 26, 2010
Example - Charged Balls
!
Simplify
!
We divide the two free-body force equations
containing the string tension
!
Thus we eliminate the string tension and get
!
Putting in our expressions for the force of gravity and
the electric force, we get
49
Thursday,
Example - Charged Balls
!
Simplify
!
We divide the two free-body force equations
containing the string tension
!
Thus we eliminate the string tension and get
!
Putting in our expressions for the force of gravity and
the electric force, we get
49
Thursday,
iClicker
! Lecture will start with iClicker question
! 5 lectures (2 1/2 weeks) are discarded,
including todays
! 100pt out of 700 total.
5
Thursday, August 26, 2010
Highlights
!
http:/www.physics.purdue.edu/academic_programs/courses/phys241/
! Grades In Blackboard
! Register I-Clicker in Blackboard (before the end of term)
! Do Reading Assignments for Lecture
! Complete Homework by 7:00 AM Mondays and
Wednesdays
! Ho
Cell phones
! Turn it off.
! If recurring problem, we will introduce a rule If it
rings: you leave the class for the whole lecture.
4
Thursday, August 26, 2010
Count # of equations and unknown (should be equal!)
T sin = Fc
T cos = Fg
Fg = mg
5=5
2
q
Fc = k 2
d
d/2
sin =
l
eliminate T
eliminate d
74
Thursday, August 26, 2010
Fundamental Forces of Nature
! Unification of forces?
! E.g., electricity and magnetism were thought
different, but actually are two sides of
the same force
! EM & weak forces are also united - electroweak
! Some ideas how to unite electroweak & strong
!
Action at distance: through fields
Charges produce fields, fields act on other charges
another charge
electric eld
electric charge (source of eld)
4
Thursday, August 26, 2010
Action at distance: through fields
Charges produce fields, fields act on other charges
electric eld
electric charge (source of eld)
4
Thursday, August 26, 2010
General Problem Solving Strategies
1.
2.
3.
4.
5.
6.
Write what is given.
Sketch
Write equations
Count # of equations and unknown (should be equal!)
Solve the system (DO NOT PLUG IN NUMBERS!)
Check dimensions (if dimensions are wrong, the answer is
wrong)
The Four Forces
! The four fundamental forces work by exchanging
elementary particles (not necessarily real, might be
virtual).
Electromagnetic - photon
Weak - W and Z bosons (observed in 1983)
Strong gluons (observed in 1979)
Gravity - graviton (?) (
! All administrative/Blackboard/iClicker/
CONNECT PLUS/attendance/scores questions
should be directed to David Koltick,
[email protected]
2
Thursday, August 26, 2010
Example - Charged Balls
Consider two identical charged balls hanging from the
ceiling by strings of equal length = 1.5 m (in
equilibrium). Each ball has a charge of q=25 C. The
balls hang at an angle ) = 25 with respect to the
vertical. What is the mass o
Example - Charged Balls
!
Consider two identical charged balls hanging from the
ceiling by strings of equal length = 1.5 m (in
equilibrium). Each ball has a charge of q=25 C. The
balls hang at an angle ) = 25 with respect to the
vertical. What is the mass
Example - Charged Balls
!
Consider two identical charged balls hanging from the
ceiling by strings of equal length = 1.5 m (in
equilibrium). Each ball has a charge of q=25 C. The
balls hang at an angle ) = 25 with respect to the
vertical. What is the mass