Physics by Dhiman Sir

🎯 Physics Challenge: Pendulum Meets a Nail!
A bob of mass m is attached to a light string of length L and released from the horizontal position. A smooth nail is fixed at a distance L/2 below the pivot.
As the string wraps around the nail, the bob starts moving in a smaller circular path.
❓ What is the angular velocity (ω) of the bob when the string first begins to wrap around the nail?
💡 Use conservation of mechanical energy and circular motion concepts.
Can you solve it without writing lengthy equations?
👇 Post your answer and method in the comments!

Writing
⚡ Can You Find the Equivalent Resistance

Between A and B?

A beautiful symmetry-based resistor network challenge!

Using equipotential points and clever circuit reduction, the complex network simplifies dramatically, leading to:
RAB = 3R/8
🔍 Key Idea: Due to symmetry, several outer nodes are at the same potential, so no current flows through certain branches. This allows the network to be redrawn and reduced easily.
💡 Physics and electrical networks become much simpler when symmetry is recognized.

❓ Did you solve it before looking at the
answer?

https://chatgpt.com/s/m_6a2454cf90c4819197e98b5eb3867d08

🔌 Physics Challenge: Equivalent Resistance Between A and B

A conducting wire forms the outer square, making all boundary points equipotential. Can you find the equivalent resistance between points A and B?

💡 Hint: Use symmetry and identify the equipotential nodes before simplifying the network.

✅ Final Result:

R(AB)=(R,+R'/)4

Can you derive it without using Kirchhoff's laws?

⚡ NEET Physics Challenge! ⚡

Three identical diamond-shaped resistor networks are connected in series. Each resistor has a resistance of 3 Ω.

🧠 Can you find the equivalent resistance between A and B without lengthy calculations?

🔹 Use symmetry and circuit reduction techniques.

🔹 A perfect question to sharpen your resistor-network concepts.

🔹 Ideal for NEET, JEE, CUET, and Olympiad preparation.

❓ What is the correct answer?
A) 54 Ω B) 18 Ω C) 36 Ω D) 9 Ω

💬 Post your solution in the comments before checking others!

🚀 Can Friction Defeat Gravity?

A block is pressed against the vertical wall of an accelerating cart. As the cart accelerates, the normal force on the block increases, generating a frictional force that can balance its weight.

For the block to remain at rest relative to the cart:

a ≥ g/μ

✨ A fascinating example of how acceleration can indirectly prevent an object from falling under gravity!

💡 Physics is not about memorizing formulas—it's about understanding how forces interact and support each other.

❓ Challenge: Can you solve this problem in less than 30 seconds?

Comment your answer below!

🚀 Can a Block Stay at Rest on an Acceleratin Incline?

Consider a frictionless block placed on a smooth inclined plane. If the wedge accelerates horizontally, a pseudo force acts on the block in the non-inertial frame.
For the block to remain at rest relative to the incline:

mg sinθ = ma cosθ
Therefore,
a = g tanθ

A beautiful demonstration of how gravity and pseudo force can exactly balance each other, keeping the block stationary on a moving incline.

💡 Physics becomes fascinating when viewed from different frames of reference!

❓Can you derive the result without using equations of motion?

Writing
🔋⚡ MCQ Challenge: Find the Potential Difference V(AB)

Two cells of emf. E1 and E2 with resistors R1 and R2 are connected as shown. Can you determine the potential difference between points A and B without lengthy calculations?

🧠 Test your understanding of: • Kirchhoff's Laws • Potential Difference • EMF and Internal Circuit Analysis • Equivalent Circuit Concepts
👇 Post your answer and method in the comments!

🔴 MCQ Challenge: Cube Resistance Puzzle

A cube is formed using identical resistors, each of resistance R. Points A and B are adjacent corners of the cube.

❓ Can you find the equivalent resistance between A and B?

A) 5R/6

B) 3R/4

C) 7R/12

D). 7R/5

Think before you calculate! Symmetry is the key. ⚡