Physical Quantities / भौतिक राशियाँ
The Physics section of the source begins by classifying physical quantities broadly into scalar and vector quantities.
Source का Physics section physical quantities को broadly Scalar तथा Vector quantities में classify करके शुरू होता है।
Scalar Quantities / अदिश राशियाँ
Physical quantities having magnitude only are called scalar quantities.
जिन physical quantities में केवल magnitude होता है, direction नहीं, उन्हें Scalar Quantities कहा जाता है।
Examples / उदाहरण
Mass, speed, volume, work, time, distance, power and energy.
Mass, speed, volume, work, time, distance, power तथा energy scalar quantities के examples हैं।
Vector Quantities / सदिश राशियाँ
Physical quantities possessing both magnitude and direction are called vector quantities.
जिन physical quantities में magnitude और direction दोनों होते हैं उन्हें Vector Quantities कहा जाता है।
Examples / उदाहरण
Displacement, velocity, acceleration, force, momentum and torque.
Displacement, velocity, acceleration, force, momentum तथा torque vector quantities हैं।
The source also states that a vector must obey the triangle rule of addition of vectors.
Newton's First Law of Motion / न्यूटन का प्रथम गति नियम
Every body maintains its initial state of rest or uniform motion in a straight line unless an external force acts upon it.
प्रत्येक body अपनी state of rest अथवा straight line में uniform motion को तब तक maintain करती है जब तक उस पर external force act न करे।
The source also calls this Galileo's law of inertia.
Source इसे Galileo's Law of Inertia भी कहता है।
Example / उदाहरण
While jumping from a slowly moving train or bus, a person should run a short distance in the direction of motion.
Newton's Second Law / न्यूटन का द्वितीय गति नियम
The source states that force acting on an object is directly proportional to the product of its mass and acceleration.
Object पर acting force उसके mass तथा acceleration के product के directly proportional होता है।
F = ma
Newton's Third Law / न्यूटन का तृतीय गति नियम
To every action there is an equal and opposite reaction.
प्रत्येक action के लिए equal और opposite reaction होता है।
Examples / उदाहरण
- Train bogies are provided with buffers to reduce severe jerks during shunting.
- A rocket moves upward due to reaction against the downward ejection of gases.
Quick Comparison / त्वरित तुलना
- Mass → Scalar
- Speed → Scalar
- Distance → Scalar
- Velocity → Vector
- Displacement → Vector
- Force → Vector
- First Law → Inertia
- Second Law → Force, mass and acceleration
- Third Law → Action and reaction