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João Gabriel A.

Rio de Janeiro State University


Currently a PhD candidate in semi-classical gravity at the Brazilian Center for Research in Physics.

My research is related to the Black hole information loss paradox. I am currently working on understanding the correlations between Hawking radiation particles and it’s partners particles inside the Black hole. My favorite topic in undergraduate physics is special relativity.
I do enjoy teaching and explaining Physics at any level. I've been teaching and explaining for 5 years now.

Other than that, I am a total fan of cartoons.

My LinkedIn:ão-gabriel-alencar-caribé-12a02516a/


BS Physics
Rio de Janeiro State University
MS Physics
Brazilian Center for Research in Physics
Phd Physics
Brazilian Center for Research in Physics

Topics Covered

Rotation of Rigid Bodies
Dynamics of Rotational Motion
Equilibrium and Elasticity
Current, Resistance, and Electromotive Force
Direct-Current Circuits
Electromagnetic Induction
Alternating Current
Electromagnetic Waves
Quantum Physics
Atomic Physics
Newton's Laws of Motion
Applying Newton's Laws
Kinetic Energy
Potential Energy
Electric Charge and Electric Field
Gauss's Law
Reflection and Refraction of Light
Wave Optics
Motion Along a Straight Line
Fluid Mechanics
Temperature and Heat
Thermal Properties of Matter
The First Law of Thermodynamics
The Second Law of Thermodynamics
Motion in 2d or 3d
Moment, Impulse, and Collisions

João Gabriel's Textbook Answer Videos

University Physics with Modern Physics

For a planet in our solar system, assume that the axis of orbit is at the sun and is circular. Then the angular momentum about that axis due to the planet's orbital motion is $L = M$$\upsilon$$R$.
(a) Derive an expression for $L$ in terms of the planet's mass $M$, orbital radius $R$, and period $T$ of the orbit. (b) Using Appendix F, calculate the magnitude of the orbital angular momentum for each
of the eight major planets. (Assume a circular orbit.) Add these values to obtain the total angular momentum of the major planets due to their orbital motion. (All the major planets orbit in the same
direction in close to the same plane, so adding the magnitudes to get the total is a reasonable approximation.) (c) The rotational period of the sun is 24.6 days. Using Appendix F, calculate the
angular momentum the sun has due to the rotation about its axis. (Assume that the sun is a uniform sphere.) (d) How does the rotational angular momentum of the sun compare with the total orbital
angular momentum of the planets? How does the mass of the sun compare with the total mass of the planets? The fact that the sun has most of the mass of the solar system but only a small fraction of its total angular momentum must be accounted for in models of how the solar system formed. (e) The sun has a density that decreases with distance from its center. Does this mean that your calculation
in part (c) overestimates or underestimates the rotational angular momentum of the sun? Or doesn't the nonuniform density have any effect?

Chapter 13: Gravitation
Section 8: Black Holes
João Gabriel A.
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