Physics (11th and 12th) by Er GK Singh

A car starts from rest and accelerates uniformly to a speed 20m/s of in 10 seconds . What distance does it cover in this time?

2 months ago | [YT] | 2

Physics (11th and 12th) by Er GK Singh

A vector has :-

2 months ago | [YT] | 2

Physics (11th and 12th) by Er GK Singh

What is the unit of force in CGS system?

5 months ago | [YT] | 3

Physics (11th and 12th) by Er GK Singh

Comment your answer!!

5 months ago | [YT] | 4

Physics (11th and 12th) by Er GK Singh

Key Points: (‪@physicsbyergksingh‬ )

If velocity increases, acceleration is positive.

If velocity decreases, acceleration is negative (deceleration).

If velocity remains constant, acceleration is zero.

6 months ago | [YT] | 5

Physics (11th and 12th) by Er GK Singh

Acceleration is the rate at which an object's velocity changes over time. It is a vector quantity, meaning it has both magnitude and direction. In physics, acceleration is typically measured in meters per second squared (m/s²) and can result from an increase or decrease in speed or a change in direction.

(‪@physicsbyergksingh‬ )

6 months ago | [YT] | 6

Physics (11th and 12th) by Er GK Singh

Physics Behind Holi: A Colorful Perspective(‪@physicsbyergksingh‬ )

Holi, the festival of colors, offers a fantastic opportunity to explore various physics concepts in a fun and engaging way. Let's dive into some key principles of physics that are at play during Holi!


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1. Scattering of Light – Why Do We See Colors?

The colors we see in Holi powders (gulal) are due to scattering and absorption of light.

Rayleigh Scattering: When sunlight passes through the fine particles of gulal in the air, shorter wavelengths (blue, violet) scatter more, making the atmosphere appear slightly bluish.

Mie Scattering: If the gulal particles are larger, they scatter all wavelengths almost equally, producing a white or pale glow.


Each colored powder absorbs some wavelengths and reflects others, which is why we see different hues like red, green, or yellow.


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2. Surface Tension – How Water Balloons Burst

Throwing water balloons is a Holi tradition. The physics behind their bursting lies in surface tension and pressure.

A balloon holds water due to the elasticity of the rubber and the surface tension of water inside.

When the balloon hits a surface, the force of impact overcomes the internal pressure, breaking the rubber and splashing water everywhere.


Fun Fact: A fuller balloon bursts more easily than a partially filled one because the stretched rubber is thinner and weaker.


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3. Projectile Motion – Throwing Water Balloons and Pichkaris

When you throw a water balloon or spray color from a pichkari (water gun), it follows a parabolic trajectory due to projectile motion.

The path depends on initial velocity and angle of projection.

Gravity pulls the water down, while air resistance slows it.

To hit a friend at a distance, aim at an optimal 45-degree angle for maximum range.



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4. Capillary Action – How Colors Spread on Clothes

When wet colors touch your clothes, they spread due to capillary action—the ability of a liquid to flow in narrow spaces without external forces.

This happens because of cohesion (water molecules sticking together) and adhesion (water molecules sticking to fabric fibers).

The finer the fabric, the faster the color spreads!



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5. Newton’s Third Law – Reaction Forces in Pichkari

Newton’s Third Law states: For every action, there is an equal and opposite reaction.

When you push water out of a pichkari, the backward force (reaction) pushes the pichkari slightly back.

Similarly, when you throw a bucket of water, your hands feel a backward push!



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6. Friction – Why Colors Stick to Skin and Clothes

The sticking of colors depends on friction between the powder particles and your skin/clothes.

Rough surfaces (dry skin or cotton fabric) hold color better due to increased friction.

Smooth surfaces (oily skin or synthetic clothes) allow colors to wash off easily.


Tip: Apply oil before Holi to reduce friction and make colors easier to remove!


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Conclusion: Science Makes Holi More Fun!

Holi isn't just about colors; it's a real-life physics experiment! Next time you play Holi, notice these principles in action and appreciate the science behind the fun.

7 months ago | [YT] | 5

Physics (11th and 12th) by Er GK Singh

Newton's Third Law of Motion

Statement:
"For every action, there is an equal and opposite reaction."

This means that whenever one object exerts a force on a second object, the second object exerts an equal force in the opposite direction on the first object.

Mathematical Representation:

If object A exerts a force F on object B, then object B exerts a force -F on object A:

F(AB)= -F(BA)

Equal in magnitude

Opposite in direction

Acting on different objects (Action and Reaction forces never cancel out each other because they act on different bodies)


Examples:

1. Walking – When you push the ground backward with your foot, the ground pushes you forward with an equal force.


2. Rocket propulsion – The rocket pushes gases downward, and the gases push the rocket upward.


3. Jumping off a boat – When you jump forward from a boat, the boat moves backward.


4. Recoil of a gun – When a bullet is fired forward, the gun moves backward with an equal and opposite force.

7 months ago | [YT] | 3

Physics (11th and 12th) by Er GK Singh

What is the work done by the tension in the string of a simple pendulum, where length of the string=2m and angle the string makes is 45 degrees.

7 months ago | [YT] | 5

Physics (11th and 12th) by Er GK Singh

Mind-Blowing Physics Fact: Time Slows Down Near a Black Hole!

Did you know that time moves slower in a strong gravitational field? This mind-blowing concept, known as gravitational time dilation, comes from Einstein’s Theory of General Relativity.

When you're close to a massive object like a black hole, time actually slows down relative to someone farther away. If you were near a black hole’s event horizon, an observer watching from a distance would see you moving in slow motion, while you’d feel normal!

This phenomenon has been scientifically proven using atomic clocks placed at different altitudes on Earth. Clocks at higher altitudes (where gravity is weaker) tick faster than those at lower altitudes.

Why Does This Matter?

GPS satellites correct for time dilation to provide accurate location data.

Astronauts in space age slightly faster than people on Earth.

If you fell into a black hole, time would nearly freeze from an outsider's perspective!

7 months ago | [YT] | 5