Vedic Mathematics Chpter 1

VEDIC MATHS, COMPUTER FUNDAMENTALS, PROGRAMING LANGUAGES( PYTHON, C, C++,JAVA) PHYSICS(9,10,11,12)

Physics Notes Class 11 UNITS AND MEASUREMENTS

 UNITS AND MEASUREMENTS

The comparison of any physical quantity with its standard unit is called measurement.

Physical Quantities

All the quantities in terms of which laws of physics are described, and whose measurement is

necessary are called physical quantities.

Units

 A definite amount of a physical quantity is taken as its standard unit.

 The standard unit should be easily reproducible, internationally accepted.

Fundamental Units

Those physical quantities which are independent to each other are called fundamental

quantities and their units are called fundamental units.

S.No. Fundamental Quantities Fundamental Units Symbol

1. Length metre m

2. Mass kilogram kg

3. Time second S

4. Temperature kelvin kg

5 Electric current ampere A

6 Luminous intensity candela cd

7 Amount of substance mole mol

Supplementary Fundamental Units

Radian and steradian are two supplementary fundamental units. It measures plane angle and

solid angle respectively.

S.No. Supplementary Fundamental Quantities Supplementary Unit Symbol

1 Plane angle radian rad

2 Solid angle steradian Sr

Derived Units

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Those physical quantities which are derived from fundamental quantities are called derived

quantities and their units are called derived units.

e.g., velocity, acceleration, force, work etc.

Definitions of Fundamental Units

The seven fundamental units of SI have been defined as under.

1. 1 kilogram A cylindrical prototype mass made of platinum and iridium alloys of height

39 mm and diameter 39 mm. It is mass of 5.0188 x 1025 atoms of carbon-12.

2. 1 metre 1 metre is the distance that contains 1650763.73 wavelength of orange-red light

of Kr-86.

3. 1 second 1 second is the time in which cesium atom vibrates 9192631770 times in an

atomic clock.

4. 1 kelvin 1 kelvin is the (1/273.16) part of the thermodynamics temperature of the triple

point of water.

5. 1 candela 1 candela is (1/60) luminous intensity of an ideal source by an area of cm’

when source is at melting point of platinum (1760°C).

6. 1 ampere 1 ampere is the electric current which it maintained in two straight parallel

conductor of infinite length and of negligible cross-section area placed one metre apart

in vacuum will produce between them a force 2 x 10-7 N per metre length.

7. 1 mole 1 mole is the amount of substance of a system which contains a many elementary

entities (may be atoms, molecules, ions, electrons or group of particles, as this and atoms

in 0.012 kg of carbon isotope 6C12.

Systems of Units

A system of units is the complete set of units, both fundamental and derived, for all kinds of

physical quantities. The common system of units which is used in mechanics are given below:

1. CGS System In this system, the unit of length is centimetre, the unit of mass is gram

and the unit of time is second.

2. FPS System In this system, the unit of length is foot, the unit of mass is pound and the

unit of time is second.

3. MKS System In this system, the unit of length is metre, the unit of mass is kilogram and

the unit of time is second.

4. SI System This system contain seven fundamental units and two supplementary

fundamental units.

Relationship between Some Mechanical SI Unit and Commonly Used Units

S.No. Physical Quantity

Unit

1 Length

(a) 1 micrometre = 10-6 m

(b) 1 angstrom =10-10 m

2 Mass (a) 1 metric ton = 103 kg

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(b) 1 pound = 0.4537 kg

(c) 1 amu = 1.66 x10-23 kg

3 Volume

1 litre = 10-32 m3

4. Force

(a) 1 dyne = 10-5 N

(b) 1 kgf = 9.81 N

5. Pressure

(a) 1 kgfm2 = 9.81Nm-2

(b) 1 mm of Hg = 133 Nm-2

(c) 1 pascal = 1 Nm-2

(d) 1 atmosphere pressure = 76 cm of Hg = 1.01 x 105 pascal

6. Work and energy

(a) 1 erg =10-7 J

(b) 1 kgf-m = 9.81 J

(c) 1 kWh = 3.6 x 106 J

(d) 1 eV = 1.6 x 10-19 J

7. Power

(d) 1 kgf- ms-1 = 9.81W

1 horse power = 746 W

Some Practical Units

1. 1 fermi =10-15 m

2. 1 X-ray unit = 10-13 m

3. 1 astronomical unit = 1.49 x 1011 m (average distance between sun and earth)

4. 1 light year = 9.46 x 1015 m

5. 1 parsec = 3.08 x 1016 m = 3.26 light year

Some Approximate Masses

Object Kilogram

Our galaxy 2 x 1041

Sun 2 x 1030

Moon 7 x 1022

Asteroid Eros 5 x 1015

Dimensions

Dimensions of any physical quantity are those powers which are raised on fundamental units to

express its unit. The expression which shows how and which of the base quantities represent

the dimensions of a physical quantity, is called the dimensional formula.

Dimensional Formula of Some Physical Quantities

S.No.

Physical

Quantity

Dimensional

Formula

MKS

1 Area [L2] metre2

2 Volume [L3] metre3

3 Velocity [LT-1] ms-1

4 Acceleration [LT-2] ms-2

5 Force [MLT-2] newton (N)

6 Work or energy [ML2T-2] joule (J)

7 Power [ML2T-3] J s-1 or watt

8 Pressure or stress [ML-1T-2] Nm-2

9 Linear momentum or Impulse [MLT-1] kg ms-1

10 Density [ML-3] kg m-3

11 Strain Dimensionless Unitless

12 Modulus of elasticity [ML-1T-2] Nm-2

13 Surface tension [MT-2] Nm-1

14 Velocity gradient T-1 second-1

15 Coefficient of velocity [ML-1T-1] kg m-1s-1

16 Gravitational constant [M-1L3T-2] Nm2/kg2

17 Moment of inertia [ML2] kg m2

18 Angular velocity [T-1] rad/s

19 Angular acceleration [T-2] rad/S2

20 Angular momentum [ML2T-1] kg m2S-1

21 Specific heat L2T-2θ-1 kcal kg-1K-1

22 Latent heat [L2T-2] kcal/kg

23 Planck’s constant ML2T-1 J-s

24 Universal gas constant [ML2T-2θ-1] J/mol-K

Homogeneity Principle

If the dimensions of left hand side of an equation are equal to the dimensions of right hand side

of the equation, then the equation is dimensionally correct. This is known as homogeneity

principle.

Mathematically [LHS] = [RHS]

Applications of Dimensions

1. To check the accuracy of physical equations.

2. To change a physical quantity from one system of units to another system of units.

3. To obtain a relation between different physical quantities.

Significant Figures

In the measured value of a physical quantity, the number of digits about the correctness of

which we are sure plus the next doubtful digit, are called the significant figures.

Computer Memory

computer memory part 1

computer Memory part 2

computer memory part 3

Computer Memory Part 4

Binary Numbers

Binary Numbers

Some numerical problems on physics for class 9 students

1. An airplane accelerates down a runway at 3.20 m/s2 for 32.8 s until is finally lifts off the ground. Determine the distance traveled before takeoff.
2. A car starts from rest and accelerates uni formly over a time of 5.21 seconds for a distance of 110 Upton Chuck is riding the Giant Drop at Great America. If Upton free falls for 2.6 seconds, what will be his final velocity and how far will he fall?
3. A race car accelerates uni formly from 18.5 m/s to 46.1 m/s in 2.47 seconds. Determine the acceleration of the car and the distance traveled.
4. A feather is dropped on the moon from a height of 1.40 meters. The acceleration of gravity on the moon is 1.67 m/s2. Determine the time for the feather to fall to the surface of the moon.
5. Rocket-powered sleds are used to test the human response to acceleration. If a rocket -powered sled is accelerated to a speed of 444 m/s in 1.8 seconds, then what is the acceleration and what is the distance that the sled travels?
6. A bike accelerates uniformly from rest to a speed of 7.10 m/s over a distance of 35.4 m. Determine the acceleration of the bike.
7. An engineer is designing the runway for an airport. Of the planes that will use the airport, the lowest acceleration rate is likely to be 3 m/s2. The takeoff speed for this plane will be 65 m/s. Assuming this minimum acceleration, what is the minimum allowed length for the runway ?
8. A car traveling at 22.4 m/s skids to a stop in 2.55 s. Determine the skidding distance of the car (assume uniform acceleration).
9. A kangaroo is capable of jumping to a height of 2.62 m. Determine the takeoff speed of the kangaroo.
10. If Michael Jordan has a vertical leap of 1.29 m, then what is his takeoff speed and his hang time (total time to move upwards to the peak and then return to the ground)?

MY DEAR MODI JI

CORONA VS PM MODI VS HATERS(CRITICS)

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And for those who are worried abt economic meltdown, and GDP you silly idiots dont have to worry about that too because if our country's GDP was not even prepare for this epidemic then its shame on us. why and for what we earn througn our life ...? just to secure our family future. so just shut the fuck up and support positively or stick your ass at home and sleep tight.