### Physical Quantities

The rules related to time can be expressed as formulas related to time, force, temperature, density and many other physical quantities. All physical quantities can generally be divided into basic (length, mass and time) and derived (speed, area, density, etc.) amounts.Physical amounts can be divided into two classes:

(1) Scalar (These have only magnitude) quantities

(2) Vector (these have both magnitude and direction) quantities.

### Vector Amount

Vector zodiac, physical quantities that have magnitude as well as direction and which are added according to certain rules of yoga, are called dubious zodiacs: like velocity, deflection, force, acceleration etc.A scalar is a physical amount that only has magnitude. No direction, it is called scalar zodiac: like mass, speed, volume, work, time, energy etc.

Note: electric current, temperature, pressure are all scalar quantities.

### The Frequency

The frequency of a repeated event (a repeated event) that occurs in unit time is called the frequency of that event. Frequency can also be understood as the rate of phase change of a sinusoidal wave. The unit of frequency is Hartz (cycles per second).The time it takes to complete a vibration is called the time period.

Periodic period = 1 / frequency

That is, T = 1 / f

### Impulse

The product of force and time period is called impulse of force.If a law force F is applied to a delta t parallel to a body, the impulse of this force will be F * delta t. Impulse is an amount. Its condition will be the same as that of force.

Let the mass of a body be m. Applying the law F to the delta t parallel to this, the velocity v changes in velocity. Then according to Newton's rules-

F = m * a = m * delta v / delta t

F delta t = m delta t

Sti m delta v = delta p

Hence F delta t = delta p

Therefore, the impulse given to a body is equal to the momentum change in the body. Therefore, the unit of impulse is also the same as that of momentum (newton.seconds).

### Work

In ordinary lore, action means physical or mental activity. When the force has motion (displacement) in the object, force is acted upon and the product of displacement in the direction of force and force expresses the work.Work = force & distance traveled in the direction of force.

W = F x d (unit of work is joule)

Power

The working rate is called power

P = w / t (unit of power is watt (w))

**The weight**

The weight of an object is the force that exerts on it due to the gravity of the earth and is acting towards the center of the earth. Whereas mass is the measure of the amount of matter contained in an object. When we say that a person weighs 60 kg. In fact, we actually tell its mass and not its weight.

**Pressure**

The force per unit area is called pressure.

The unit of pressure is Newton per square meter. Or Pascal. Atmospheric pressure: There is a very high level of air around the earth called the atmosphere. There is a weight of air, so it puts pressure not only on the surface of the earth, but on all the objects on the earth. In fact, the atmospheric pressure of human and ocean is measured by a barometer.

**Energy**

It neither has mass nor does it occupy space but it exists in the entire universe. The ability to work is produced only by energy. No work can be done without energy expenditure. There are many types of energy, such as mechanical, thermal, optical, sound, magnetic, electrical, nuclear, chemical energy, etc.

**Gravity**

An attraction force acts between two bodies according to Newton's gravity. If one of these bodies is earth, then this attraction force is called gravity. That is, gravity is the attraction force through which the earth pulls an object towards its center. The acceleration generated due to this force is called gravitational acceleration (g), which has a value of 9.8 m / s ^ 2.

Gravitational acceleration (g) does not depend on the form, shape, mass etc. of the object.

**Speed**

If an object moves in relation to time relative to other objects, then this state of the object is called motion (motion).

In general terms, the meaning of motion - change in the state of vastu is called motion.

**Density**

Mass / Volume Its S.I. The unit is kilogram meter ^ -3.

Trick

The rate of displacement of an object is called speed. Ie speed = distance / time This is a scalar amount. Its S.I. The unit is m / s.

**Acceleration**

The rate of change in velocity of an object is called acceleration. Its S.I. The unit is 2 m / s. If the velocity of the object decreases with time, the acceleration is negative, which is called retardation.

**Distance**

The distance traveled by the object in a given time period is called the distance. This is a scalar sign. It is always positive (+ ve).

**Mass number**

The mass number is called the atomic weight. This is the total number of protons and neutrons. It is not the same as the atomic number.

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**See Also:**

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### Newton's law First,Second and Third law

"Newton's laws of motion": Newton, the father of physics, propounded the first law of motion in his book ""

*Principia*"" in 1687 AD.

**Newton's first law of motion:**If an object is in a resting state, it will remain in the resting state or if it is moving in a straight line at the same speed, it will continue as long as it But do not change its present state by applying any external force.

*The first law is also called Galileo's law or law of inertia.*

Inertia is the tendency of an object to maintain its state of rest or state of equal motion in the absence of external force.

The first rule gives the definition of force.

Definition of force: Force is the external factor that changes or tries to make changes in the initial state of an architecture. Force is a vector amount. Its S.I. The unit is Newton.

**Some examples of inertia;**

(i) When a stopped motor or train suddenly stops, the passengers sitting in it lean backwards.

(ii) On the sudden stop of a moving motor car, the passengers sitting in it lean forward.

(iii) Holding the blanket by hand and beating it with the pole, the dust particles fall.

Emotion: The product of mass and velocity of an object is called the momentum of that object. Ie momentum = velocity x mass

This is a vector amount. Its S.I. Unit kg x m / s. is.

**Newton's second law of motion:**The rate of change in momentum of an object is proportional to the force exerted on that object. And the momentum is in the direction of change. Now if the force F, the acceleration produced in the direction of force a and the mass of the object is m, then f = ma from Newton's second law of motion i.e. that Newton's second law gives the expression it happens.

**Note:**The first rule is part of the second rule.

**Newton's third law of motion:**Each action is equal, but reacts in the opposite direction. Examples:

(i) When the gun is fired, the driver is pushed backwards

(ii): Reversing when jumping from boat to shore

(iii): In flying the rocket.

**The force**

Force is the external factor that changes or tries to change the initial state of an architecture. Force is a vector amount.

*Its S.I. The unit is Newton.*

**Concentration force**

When a particle makes circular motion with uniform speed, an acceleration work towards its center is called its centripetal acceleration. By Newton's law of motion, the acceleration in a particle always arises from the force itself and the direction of the force is proportional to the acceleration. Hence, a force always acts in the direction of the center on the particle moving the circular motion. this

Force is called centripetal force. For the circular motion of a particle, this force must be applied on it.

**Unit**

To measure a physical amount, we compare this amount to a certain, baseline, randomly chosen, recognized reference standard. This reference standard is called standard unit.

**Quantity of Physical Amount**

The measurement of any physical amount is expressed by writing a numeric number in front of the unit. This is called the magnitude of that physical amount.

**Basic unit**

Although the number of physical quantities we measure is very large, yet, we need only a limited number of units to express all these physical quantities, as these quantities are interrelated.

The units used to express the basic quantities are called root units. These units do not depend on other units but they are independent in themselves. "

**Derived unit**

The units of all physical quantities, other than the original ones, can be expressed by combining the basic units. The units of the derived quantities thus obtained are called derived units. Derived units depend on the original units.

**System of units (or method)**-

The entire set of root units and derived units is called the system (or method) of units.

Different systems of units -

For many years, scientists from different countries used different measurement systems for measurement. Until now, three such systems were used prominently before -

1. CGS System

2. FPS (British) System

3. MKS System

The basic units of length, mass and time in these systems are as follows: -

1. CGS System - Centimeters, grams and seconds.

2. FPS System - Foot, Pound and Second.

3. MKS System - Meter, Kilogram and Second.

**International System of units-**

Nowadays an internationally recognized system i.e. International System of Units (SI System) is used. It is called 'System International de Units' in French. It is written SI in the initials. The scheme of SI symbols, units, and their abbreviations was developed in 1971, approved by the General Assembly of Mapatol, for international use in scientific, technical, industrial and commercial work.

Due to the (decimal or decimal) trend of SI units based on powers of 10, conversion under this system is very easy and convenient.

**Seven basic units of SI system-**

SI unit unit name symbol SI unit

1. Length m

2. mass kg kg

3. Time seconds

4. Electric current ampere A

5. Thermodynamic Heat Calvin K

6. Mole volume of the substance

7. Light-intensity candela cd

Dimensions

To extract the derived units of physical quantities, the powers that are required to be placed on the units are called dimensions of that amount. If the dimensions of an amount are a in length b in mass and c in time and d in temperature, then the dimensions of that amount are displayed as follows-

(La Mb Tc Qd)

Dimensional formulas of major physical signs

Dimensional formulas related to other physical zodiacs

Area = Length × Width (L2)

Volume = Length × Width × Thickness (L3)

Velocity = Displacement / Time (LT-1)

Acceleration velocity change / time LT-2

Impulse Force × Time MLT-1

Force mass × acceleration MLT-2

Work force × Displacement ML2T-2

Power work / time ML2T-3

Density Mass / Volume ML-3

Emotion mass × velocity MLT-1

Pressure force / area ML-1T-2

Force Momentary Force × Distance ML2T-2

Force force / area ML-1T-2

Increase in deformation length / initial increase L0

Page tension force / length MT-2

Angular velocity angle / time T-1

Inertial moment mass × (distance) 2 ML2

**Displacement**

The vertical distance between two points in a certain direction is called displaced. This is the vector sign. Its S.I. The unit is a meter. Displacement can be positive, negative and zero.

**Velocity**

The rate of displacement of an object or the distance traveled by an object per second in a certain direction is called velocity. This is a vector sign. Its S.I. The unit is m / s.

**Derived unit**

The units obtained by placing appropriate powers on one or more root units are called derived units, that is, derived units depend on the original units. Some derived units are as follows-

• Area = Length × Width

Unit of area = m × m = m 2

• Volume = Length × Width × Height

Unit of volume = m × m × m = m 3

Density = mass / volume

Unit of density = kg / m 3

• Velocity = displacement / time

Unit of velocity = meter / second

• speed = distance / time

Unit of speed = meter / second

• Acceleration = velocity-change / time

Unit of acceleration = meter / second / second = meter / second 2

• Force = mass × acceleration

Unit of force = kg × meter / second 2 = kg – meter / second 2 = newton

**Momentum**

The product of mass and velocity of an object is called the momentum of that object. Ie momentum = velocity x mass

This is a vector amount. Its S.I. Unit kg x m / s. is.

**Potential energy**

The potential energy depends on the mass of the object, the distance from the center, and the force of gravity. Its international unit unit is similar.

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