All physics explained in 15 minutes

All physics explained in 15 minutes

Five areas of physics worth remembering: Classical mechanics, energy and thermodynamics, electromagnetism, Relativity, and Quantum Mechanics. Classical mechanics – two main concepts worth knowing. The first is Newton’s second law: F= ma: Force equals mass times acceleration. If you apply a force to a fixed mass, it tells you how much acceleration you will get. And knowing acceleration which is the change in velocity, you can make predictions.

The second equation is the law of universal gravitation.

Energy is not a vector like force or momentum, but it is just a number.

Gravitational potential energy is expressed as PE = m g h – mass times the gravitational acceleration times the height.

Thermodynamics is the study of work, heat, and energy on a system. We showed energy is how much work you could do.

Entropy is a measure of disorder, or more accurately, the information required to describe the micro states of a system.

Electromagnetism is the study of the interaction between electrically charged particles.

Special Relativity: Einstein presumed that the speed is the same in any frame of reference.

General relativity: Later Einstein showed using the same assumptions, there would be no way to tell if you were in an accelerating reference frame or standing stationary on earth.

Quantum mechanics: Three principles are important.

The second is the Heisenberg’s uncertainty principle

Third is Schrodinger’s equation: prior to measurement, quantum systems are in superposed states. This means that their properties can only be expressed as a wave function.