National High Magnetic Field Laboratory
Jointly run by FSU, UF, and Los Alamos National Laboratory
45 tesla magnet --- highest static
magnetic field in the world
Strong electromagnets
generate BIG forces
Strong electromagnets
consume enormous
electric power.
Classical Mechanics vs Electricity and Magnetism
Classical Mechanics
Electromagnetism
(Mechanics of macroscopic
objects whose velocity is much
smaller than the speed of light.)
Newton’s three laws
(Only one of the laws is an
equation.)
Four laws
(Every one of them is an
equation.)
Newton’s three laws and relations
derived from them hold for objects
experiencing electromagnetic forces.
Law 1: Coulomb’s Law
(Gauss’ Law, which will appear
in Ch. 23, is equivalent to
Coulomb’s Law.)
CHECKPOINT 1
A
Copper Copper
D
?
B
A
D
B
?
A
D
The electrostatic force
obeys Coulomb’s Law and
Newton’s third law.
CHECKPOINT 2
e
p
distance d
p
d
Q1: The direction of the electrostatic force on
the central proton due to the electron?
Q2: The direction of the electrostatic force on
the central proton due to the other proton?
Q3: The direction of the net electrostatic force
on the central proton?
QUIZ
-1х10-16 C
3х10-16 C
1m
Q1: What will happen to the electrostatic
forces, if the distance is doubled?
Q2: Now keep the distance and the amount of
charge of the pink particle unchanged. How
must the charge of the grey particle be
changed in order to weaken the electrostatic
forces by the same amount?