Upload
jakobe-dominick
View
213
Download
0
Tags:
Embed Size (px)
Citation preview
PT UNIT 1 Subunit 3
• Newton’s Universal Law of Gravitation
• Every Object in the universe attracts every other object with a force that (for two bodies) is directly proportional to the mass of each body and that is inversely proportional to the square of the distance between them.
2
211-
221
10 x 6.67G
constant nalgravitatio universal
kg
mN
Gd
mmGFg
NF
km
kgkgkg
mN
d
mmG
kgmNkmd
kgkgm
g
e
20
25
2224
2
211-g
221
g
2
211-5
22m
24
10 x 98.1
)10 x 85.3(
10 x 7.3610 x 98.510 x 67.6F
F
10 x 6.67 G 10 x 85.3
10 x 7.36m 10 x 98.5
• Two kinds of charges
• Positive and Negative
• Charges cause electrical force
• Law of Charges: Like charges repel and unlike charges attract.
• the origin of electrical charge is the atom. All matter is made of atoms.
• In the center of the atom is a nucleus that contains positive charged protons.
• The charge of a normal atom is zero.
• Charges can be transferred from one object to another by adding electrons.
• A neutral atom has a zero charge. Adding electrons to a neutral object makes a negative charge object. Taking away electrons from a neutral object makes a positive charged object.
• Principle of conservation of charge: The net charge in an isolated system never changes.
• Coulomb’s Law
• Elementary Charge is the charge of one electron or one proton.
C
C19-
-19
10 x 1.60-Electron an of Charge
10 x 1.60proton a of Charge
chargesbetween distance d
coulombsin measured charges are q & C
mN10 x 9.0 K
Force Electrical
F
2 1
2
29
221
e
q
Fd
qqK
e
N
kg
kgkg
kg
mNF
m
kg
mNmd
kgkgm
g
p
e
47-g
227-
27-31-
2
211-
2
eg
2
211-11-
-27p
-31
10 x 7.3F
10 x 1.7
10 x 1.710 x 1.910 x 6.67
d
mGF
10 x 6.67G :10 x 3.5
10 x 1.7m :10 x 1.9
NF
mCmN
CmN
C
mNF
d
qqKF
mC
mNK
CCq
e
e
pee
e
8-
11-
2
29
2
29
2
29
2
11-2
29
-19p
-19
10 x 2.8
10 x 5.3
10 x 0.910 x 0.910 x 0.9
10 x 5.3d :10 x 0.9
10 x 6.1q :10 x 6.1
3947-
8-
g
e 10 x 2.210 x 7.3
10 x 2.8
F
F
is force lgravitiona
toforce electrical of ratio The
N
N
• A mass as potential if it is moved through a gravitational field.
• A charge has potential if it is moved through an electric field. The field creates an electrical potential between A and B.
• Electrical forces create a voltage difference whenever the positive and negative charge are separated.
systems electricalin mover
prime theis difference Potential
difference potential
or potential electric V
Voltsin measured Is
VAB
V
dE
• Voltage act like a force in an electrical system. It causes electrons to move.
• Electrons are negative charged particles found in the outer part of the atom.
• Voltage is the forcelike quantity in electrical systems.
• Voltage is measured in volts.
• A flow of charge is called a current.
• Electric systems are made of (1)Voltage source) (2) conductors (3) Control elements (4) load
• Voltages source-Battery, electrical plug in, generator
• Conductors-wires
• Control element- switch
• Load-appliances, lights, etc
• Electrical circuit is a closed path made by connecting voltage sources, control elements and loads.
• Two types of electricity.
• Direct current (DC) is current that moves in one direction only.
• Alternating current (AC) is current that moves back and forth in the wire.
• Current is movement of electrons.
• Dry cell batteries uses a paste material that contains the chemical that produces the voltage.
• Wet cell batteries use a liquid material that contains the chemical to produce the voltage.
• Primary cells are those cells that cannot be recharged.
• Secondary cells are those cells that can be recharged.
• The terminals of a battery are called electrodes.
• The positive electrode is called the Anode.
• The negative electrode is called the cathode.
• Connecting voltage sources in series so they add together requires that the positive electrode from one source is connected to the negative electrode of the other source.
• Main sources of AC are generators and electrical outlets.
• The rate at which the current is changing back and forth is its frequency (f)
• Units are cycles/sec = hertz
• Voltage difference can be created by• (1) Chemical means –Chemical energy in dry or
wet cells separates the charges to form a positive pole and a negative pole.
• (2) Magnetic/Mechanical– A coil of wire moving in a magnetic field produces a force on electrical charges that separates the positive and negative charges.
• (3) Light- light energy that falls on certain materials causes the separation of electrons from their atoms.
• Voltage is measured by using a volt meter, panel meter and a oscilloscope and a multimeter.