This document contains definitions and explanations of various physics concepts across multiple topics in mechanics, waves, heat, electricity, modern physics, and nuclear physics. It is organized as a series of menus with questions and short answers about key terms.

1. Resume
Preliminary concepts
Mechanics
Waves
Heat and Thermo
Electricity & Eletromag
Modern Physics
The Atom

2. They are defined by their magnitude only. They are treated simply as numbers in the
mathematics operations involving them.
Scalar quantities
They are defined by both their magnitude and direction. Mathematics operations
involving vectors require both the magnitude and the direction to be included.
Vector quantities
What may be implied, given as compass headings, or given as Cartesian Coordinates
The direction of a vector
What is the vector formed when two or more other vectors are combined.
Resultant vector
What may be broken into its x and y components.
Every vector
How is called a vector whose magnitude is exactly equal to and opposite in direction of
a given vector.
An equilibrant vector menu

3. What is Statics ?
-The study of objects that are not free to move.
Objects that are not free to move are in:
-Equilibrium.
The two conditions of equilibrium are:
—The sum of all applied forces is equal to zero and the sum of all applied torques is equal to zero.
What is defined as the product of a force multiplied by its lever arm.
-torque
What is defined as the perpendicular distance from the line of an applied force to the pivot point.
-A lever arm
What passes through the pivot point that causes no torques.
-Lines of force
How is called the point from which all the weight of an object is considered to act.
-The center of gravity (CG)
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4. What is Displacement?
-It is the straight-line distance between two points.
What is Velocity?
-It is the time-rate change in displacement.
What is Acceleration?
-It is the time-rate change in velocity.
What is the condition where the only force acting on an object is the earth’s gravitational
attraction.
-Free fall
All objects in free fall near the earth are accelerated toward the earth at a constant acceleration
of :
-9.8 m/s2.
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5. Objects in free fall that are moving in a curved path can be viewed as having
linear motion on both:
-the x and y axis simultaneously.
The horizontal motion (x axis) and the vertical motion (y axis)
of a projectile are
- independent of one another
The time during which an object is in free fall is:
-the length of time an object can be moving along the x axis when the object
exhibits curvilinear motion.
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6. Newton’s First Law of Motion is called:
the Law of Inertia
Newton’s Third Law of Motion is called:
-the Action-Reaction Law
Newton’s Second Law of Motion stated in equation form:
F = ma.
Frictional forces oppose:
the movement of objects
The coefficient of friction is defined as:
the ratio of the frictional force to the normal force of an object
The normal force (FN) always acts:
perpendicular to the surface from which it emanates.
Force is a:
vector quantity.
U=
F f
N
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7. Energy cannot
be created nor can it be destroyed.
Work is the product
of a force and a displacement.
Kinetic Energy is
the energy of a moving object.
Potential Energy is
the energy of position or condition.
Work, potential energy, and kinetic energy are
the same quantities.
The rate at which work is done is called:
power
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8. The symbol P is used to
represent momentum.
mv also represents
momentum.
Ft is an impulse. It produces a change in
momentum mΔv.
The law of conservation of momentum is stated:
The momentum of an isolated system remains constant.
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9. The force that produces uniform circular motion is called
centripetal force.
Newton’s Law of gravitational force describes the mutual force of
attraction between any two bodies in the universe.
Kepler’s laws describe the motion of the
planets and satellites (third law) in the solar system.
The actual weight of an object depends on
its position in a gravitational field.
Weightlessness is caused by the
constant free fall of a body in orbit.
Angular quantities all have linear equivalents (analogs), so the angular equations are identical
to the linear equations except that
θ, ω, and α must be substituted for s, v, and a.
A rolling or spinning wheel exhibits both linear motion and angular motion, which are related
by
the tangential quantities. menu

10. • Waves are
periodic vibrations that carry energy.
• Interference can be
constructive or destructive.
• The velocity of a wave is a
• Sound is a
• Light is a
longitudinal wave.
transverse wave.
• Mirrors reflect
product of its frequency and wavelength v = λ
f
light.
• The law of reflection is stated as
• A concave mirror reflects light toward the
• A convex mirror reflects light as
if
∠i = ∠r.
focal point.
the rays had passed through a focal point on the other side of the mirror.
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11. • The mirror equation:
1f
=
• Light passing between two transparent materials is
• Snell’s Law is
n1 sinθ1=n2 sinθ2
• A convex lens (converging)
• A concave lens (diverging)
1
p +
1q
is the same for both concave and convex mirrors: f is positive for concave mirrors, and f is
negative for convex mirrors.
refracted at the surface boundary of the materials.
where n is the index of refraction for the materials, and θ is the angle of refraction.
refracts light toward a focal point.
refracts light as if it had passed through a focal point and the other side of the lens.
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12. • The lens equation
1f
=
1
p +
1q
is identical in form to the mirror equation. However, q is positive when the image is located on the
opposite side of the lens from p the object.
• Light that has had all its vibrations eliminated except for those on a single plane
is plane polarized.
• Diffraction is the ability of
waves to bend around barriers placed in their way.
• Interference is the constructive or the destructive
superposition of waves with one another.
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13. • There are no temperature changes
during
• Most substances expand when they are heated and contract when they cool.
Water is a notable exception.
• The Kinetic Theory explains
• The ideal gas law is
PV =
nRT.
• The combined gas law is
the actions of gases.
(P1)(V 1)
T 1
=
a phase change.
(P2)(V 2)
T 2
• Robert Boyle determined the relationship between
the pressure and the volume of an enclosed gas.
• Jacques Charles determined the relationship between
the pressure and temperature of a gas at constant volume.
• Jacques Charles determined the relationship between
the volume and temperature of a gas kept at constant pressure.
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14. • The first law of thermodynamics is a restatement of the law of conservation of heat energy.
ΔQ = ΔU + ΔW
• The second law of thermodynamics states that
• An alternate statement of the second law is that
• The work done by a heat engine is
• A heat engine operating in reverse produces
• Calorimetry is the study of
• A substance that loses heat has
• A substance that gains heat has
no heat engine can have efficiency equal to 100%.
an ordered system tends to become disordered.
the area under its P–V curve.
cooling.
heat transfer between objects.
a negative change of heat (−ΔQ) .
a positive change of heat (+ΔQ) .
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15. • Charged particles are called
• Electrostatic charge is caused by
• Objects with a positive charge have
• Objects with a negative charge have
• Like charges repel, and unlike
• The unit of charge is
• Electric fields exist
• Electric field lines leave
• Electric field lines enter
• Electric field lines are parallel
• The electric field between a pair of parallel plates
• Capacitors store
ions.
the transfer of electrons from one object to another object.
a deficiency of electrons.
an excess of electrons.
charges attract.
the coulomb.
around all charged objects.
a positively charged object.
a negatively charged object.
between charged parallel plates.
is uniform.
electric charge or energy.
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16. • Batteries supply energy to electric circuits. The energy is measured in
• Current is the flow of charged particles and is measured in
• Resistance is opposition to current flow, and it is measured in
• The resistance of a series circuit is
• The resistance of a parallel branch of a circuit is equal to
• Like magnetic poles repel, and unlike magnetic poles
• Magnetic field lines leave north poles and enter south poles to form
• The intensity of a magnetic field called magnetic flux is measured in
volts (V).
N
( A)(m)
or tesla
amperes (A).
ohms (Ω).
the sum of resistors in the circuit.
the reciprocal of the sum of the reciprocals of the resistors in parallel.
attract.
closed loops.
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17. • Max Planck theorized
• Planck’s constant is
the particulate nature of light.
6.6×10−34 J • s
• Albert Einstein used Planck’s particulate nature of light theory to
• Planck called light
particles quanta.
• Einstein called light particles
photons.
• The higher the frequency of the light,
• Photons of light have the ability to
the more energy it carries.
explore the photoelectric effect.
• The ability of photons of light to knock electrons from the surface of some metals is called
the photoelectric effect.
energize electrons from some metals.
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18. • The work function of a metal is equal to
• Louis de Broglie theorized the existence of
Φ =hf .
matter waves.
• The two postulates of Einstein’s theory of relativity are:
1. The speed of light in a vacuum is the same for all
Observers.
2. The laws of physics are the same for all observers
moving at a constant speed.
• Moving clocks tick out time
more slowly than still clocks.
• The relativistic equation is √1−(
vc
2
)
• The relativistic mass of an object is much greater than its rest mass, leading to the equation
E=mc2
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19. • The three basic parts of an atom are
• They are the negative part of the atom. They are found outside the nucleus and they are only
1/1836 the mass of a proton.
• They are the positive part of the atom. They are found in the nucleus and their mass is 1836 times
greater than that of the electron.
• They are neutral. They have no charge, are found inside the nucleus, and have a mass
approximately equal to a proton.
• The lowest energy orbital is called
• Unexcited electrons normally occupy the ground state
• Electrons absorb energy to
• Electrons emit energy as
• E xcept for hydrogen, all atoms have
the electron, the proton, and the neutron
Electrons
Protons
Neutrons
the ground state.
n = 1.
change to a higher energy level.
they drop to a lower energy level.
neutrons and protons in the nucleus. menu

20. • What is a form of an element that has the same atomic number as the element but has a different
atomic mass?
An isotope
• The Z number of an atom is
the number of protons in the nucleus.
• The A number of an atom
is
• Atomic nuclei are held together by energy
called
the number of the protons plus the neutrons in the nucleus.
• The source of the binding energy is
the mass defect.
• Balanced nuclear equations require that:
binding
energy.
1. the sum of the atomic numbers on both sides of the equation must be equal.
2. the sum of the mass numbers on both sides of the equation must be equal.
• What is a process by which large atomic nuclei are split to obtain energy?
Nuclear fission
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