Compilation of theories and formulas

1. PHYSICS
A project compilation of theories and formulas.
Prof. Fernando V. Hidalgo, RRT MaED , Program Head RT
College of Health Related Sciences
Olivarez College, Paranaque City
Submitted by: Khan Mozahadi, Lenmae A.
BS Radtech 3

2. INTRODUCTION

3. Fundamental Quantities
• Definition
They can be obtained only by directive
observation of physic phenomenons.
There are seven fundamental quantities.
• Properties
BASE QUANTITY SYMBOL
Length m
Mass kg
Time s
Thermodynamic
temperature
k
Electric Current A
Amount of
substance
mol
Luminous
Intensity
cd

4. Derived Quantities
• Definition
Derived quantities are those defined in
terms of seven fundamental quantities.
• Properties
Here are some derived quantities:
Derived Quantities NAME
Speed, Velocity Meter per sec.
Acceleration Meter per sec. squared
Force Newton
Mass density Kilogram per cubic
meter
Pressure, stress Pascal
Power, radiant flux watt
Energy, work joule
Electric Charge coulumb

5. Scalar Quantities
• Definition
They are the quantities that are
completely described by a number that
represents its value.
• Properties
The number that defines the measure of a
scalar is called “module” or “intensity”.
For example, the temperature of a room
is 21 degree celcius.

6. Vector Quantities
• Definition
Vector quantities are physical quantities
that have both magnitude and direction.
• Properties
The scalar product of two vectors can be
constructed by taking the component of
one vector in the direction of the other
and multiplying it times the magnitude of
the other vector. This can be expressed in
the form:

8. The vector product is a vector
perpendicular to the two initial vectors,
as shown in the figure:

9. Addition of vectors (parallelogram law)
If two vector quantities are represented by two
adjacent sides or a parallelogram then the
diagonal of parallelogram will be equal to the
resultant of these two vector.

10. • Addition of vectors (tip to tail method)
To sum two vectors, A and B, simply move them
such that tip of one vector is attached to the tail of
the other. The sum of the two vectors is the vector
that goes from the tail of A to tip of B.

11. Measurement Error
• There are two types of errors: the
accidental errors are due to causes easily
detectable, usually due to small
variations in the environment, the ability
of the experimenter etc.
• Systematic errors are, instead, due to
defects of the measuring instruments or
incorrect methods measurement.
• These errors, usually, are eliminable.

12. MOTIONS

13. Frame of Reference
• Definition
A frame of reference is the set of objects in
relation to which the motion occurs with the same
characteristics.
• Properties
According to the frame of reference taken, the
motion takes on different characteristics:
E.g: A train that is in motion, is in motion with
respect to the rails and to the station from which
it departed, but it is stationary with respect to
passengers who is carrying.

14. Average speed and
instantaneous speed
• Definition
The average speed of a object in a given time
interval is equal to the ratio between distance
covered and the time interval used to cover it. In
formulas:
The instantaneous speed is the limit to which the
average speed tends when it is calculated in a
time interval always smaller.

15. • Properties:
The speed is a derived quantity, since it is related
to two fundamental quantities (distance and time
interval). It is measured in meters per second.
To transform a speed from
km/h to m/s just,
divide it by 3.6

16. Acceleration
• Definition
It is the physical quantity which
expresses how quickly changes the
speed of a body over time.
• Properties
The average acceleration is the
ratio between the change of speed
of an object and the interval of time
during which this change occurs. In
formulas:

17. The instataneous acceleration is
the average acceleration measured
in a time interval so small as to
tend to zero. In formulas:

18. FORCES and EQUILIBRIUM

19. Forces
• Definition
It is a physical quantity that alters
the state of rest or motion of an
object. In the International System
was chosen as the unit of measure
for the forces the ‘newton’ and it is
denoted by the symbol N. The force
is indicated as follows:

20. • Properties
The forces are vectors because, in addition to
having a verse, a module and a direction, can be
added as vectors, with the tip-to tail method or
with the parallelogram law.
- Point of Application
It is the point on which the force acts and from
which starts the arrow that represents the force.
- Reaction force
It is the force applied by the constraint to prevent
the movements of the rigid body. The reaction
force depends on the force to which must react.

21. Equilibrium
• Definition
It is the condition under which a body initially at
rest remains at rest.
• Properties
Condition of equilibrium for a material point.
The sum of all the forces applied is equal to the
null vector.
Equilibrium of a material point on an inclined
plane.

23. To make the material point remains in
equilibrium it must decompose the force of
gravity P into two components: one parallel to the
plane and the other perpendicular. This will be
countered by the reaction force. So in order to
balance the material point is necessary to apply a
force equal in intensity to the perpendicular
component, but in the opposite direction.
- Equilibrium for a rigid body
A rigid body is in equilibrium when the sum of
the applied forces is null and if the resultant of
the moments of all forces is equal to the null
vector.
- Stable equilibrium
It is when a body, after being subjected to a small
disturbance, tends to return to the position of
departure.

24. - Unstable Equilibrium
A body is in unstable equilibrium, if it moving
slightly from its equilibrium position, tends to
reach a new equilibrium position.
- Indifferent equilibrium
It is when a body, moved from its equilibrium
position, remains stably in the new position.

25. Weight force, mass and
weight
• Definition
The “weight force” is the force of gravity with
which the mass of the Earth (or of another planet)
attracts every body towards its center. The “mass”
is the measure of the amount of matter present in
a body; The “weight” is the force of gravity which
is exercised on every mass close to a celestial
body.
• Properties
- The mass is measured in kg (or in its multiplies
and submultiples);
- The mass is a scalar quantity;
- The mass does not change varying its position in
space;
- The weight is a force and thus a vector quantity
and it is measured in Newton;
W= m.g *g-acceleration of gravity and
measures 9.8 m/s ^ 2

26. Satellite Motion
• Definition
If a projectile is launched out of Earth’s
atmosphere, in the horizontal direction with a
speed sufficient, it will not more fall back on the
Earth. In this motion the projectile becomes a
satellite.
• Properties
- The hyperbolic trajectory is the trajectory along
which a projectile turns away, while the parabolic
trajectory is that described by a projectile
launched with the lowest speed sufficient to does
not allowing it to fall on the ground.

27. • Centripetal Force
It is the force directed towards the center that
undergoes a body which moves with uniform
circular motion.
• Centrifugal Force
It is an apparent force to which each body is
subjected when it is in a frame of reference in
rotation.

28. DYNAMICS

29. First Law of Motion
• Definition
It is also called ‘law of inertia’ and it is constituted
by two statements:
1) If the total force applied on a material point is
equal to zero, then it moves at a constant speed;
reciprocally,
2)If a material point moves at a constant speed,
then the total force that undergoes is equal to
zero.
• Properties
INERTIA
It is the tendency of a body to maintain
unchanged its state of motion (or rest)

30. - The frame of reference in which the principle of
inertia is valid are called ‘inertial systems’. There
are however also frames of reference in which the
principle of inertia is not valid.
- The principle of inertia does not apply in an
accelerated frame of reference with respect to an
inertial frame of reference.

31. Second Law of Motion
• Definition
This law says that the acceleration of a material
point is at every moment directly proportional to
the applied force; force and acceleration always
have the same direction.
• Properties
- Force and acceleration are directly proportional.
- This law establishes quantitative connection
between the resultant of the forces applied to an
object (the cause) and the acceleration produced
(that is the effect of the force).

33. Third Law of Motion
• Definition
For every action, there is an equal and
opposite reaction.
The statement means that in every interaction,
there is a pair of forces acting on the two
interacting objects. The size of the forces on the
first object equals the size of the force on the
second object. The direction of the force on the
first object is opposite to the direction of the force
on the second object.
Forces always come in pairs - equal and opposite
action-reaction force pairs.

35. Principle of Relativity
• Definition
The laws of physics are the same in all inertial
frames of reference that move between them with
uniform rectilinear motion.
• Properties

36. Work of a Force
• Definition
In physics, the work W made by a constant force
F is equal to:
• Properties
In the International System is used as a unit of
measurement for the work the ‘Joule’ (J)
- Positive work
It occurs when the force and the displacement
have the same direction.

37. - Negative work
It occurs when the force and the displacement
have opposite directions.
- Work of a variable force
When the force is not constant, for example in the
case of a spring, the work made is equal to:
W= ½ ks^2
- Work of the interaction forces between
two bodies
When two bodies interact with each other with
equal and opposite forces with intensity equal to
F and with the variation of their distance equal to
the vector r, the work made by the forces of
interaction in the case of this displacement is
equal to:
W= F. r

38. - Conservative and dissipative forces
When the work that does a force not depends on
the path taken, but only from the starting point
and from the end point, it is said that the force is
conservative. All non-conservative forces are
called dissipative forces.

39. Power
• Definition
The power is equal to the ration between the work
and the time taken to make it.
P = W / t
• Properties
- The unit of measurement of this quantity in the
International System is the watt (W).
- The power that a force must provide to move the
body at a constant speed is equal to the product of
the force and speed.
P = Fv

40. Kinetic Energy

42. Potential Energy

45. Linear Momentum

47. Angular Momentum

49. Kepler’s Laws

52. Gravitation

56. GASES and LIQUIDS

57. Density and Pressure

59. Fluids in Motion

61. HEAT and Temperature

63. Thermal Expansion

65. Heat

67. Melting

69. Solidification

70. Vaporization

72. Condensation

74. Sublimation

75. THERMODYNAMICS

76. Thermodynamics

77. First Law of
Thermodynamics

78. Second Law of
Thermodynamics

79. WAVES and ACOUSTICS

80. Waves

83. Acoustic Wave

85. Doppler Effect

87. Electromagnetism

88. Electric Charge

90. Conductors and Insulators

91. Coulomb’s Law

92. Electric Field

93. Magnetic Field

94. Electric Current

95. Ohm’s Law

97. Electrical Circuit

99. Electromagnetic Waves