UNIT 4: ENERGY
Brief Overview
Energy is everywhere in many forms. It is in us at every moment of the day in some different form always. Energy has been there since the beginning of the universe, the same level at which it is present today.
TERMINOLOGY
KINETIC ENERGY
Kinetic Energy is the energy the body possesses as a result of it being in motion.
POTENTIAL ENERGY
Potential Energy is the energy that is in an object when it is stationary. All objects have this as a result of gravity acting on it.
CHEMICAL ENERGY
Chemical energy is the energy that would be released when the object undergoes a chemical transformation and the energy turns into a different substance.
UNIFORM CIRCULAR MOTION
Uniform Circular Motion
Uniform Circular Motion is the motion of a particle moving at a constant speed on a circular path. The speed is constant throughout but the velocity keeps changing because the direction is constantly changing.
VELOCITY CALCULATIONS
There are multiple types of velocity in a circle and different ways to calculate each. Tangental velocity is the linear speed of any object moving on a linear path. Angular Velocity is the rate of change of angular position on a rotating object.
TANGENTIAL VELOCITY
The formula for Tangential Velocity is Vt = ω r, where ω represents the angular velocity of the object and r is the radius. This formula can also be rewritten in order to find the angular velocity when given the tangiental velocity as ω = Vt/r and also can be rewritten to find the radius as r= Vt/ω. This equation is very useful because tangiental velocity gives us the speed of an object.
ANGULAR VELOCITY
Angular Velocity can be found with the formula ω = change in theta over the change in time. This can be said as radians per minute, degrees per second, revolutions per minute, or anything like that.
https://www.britannica.com/science/uniform-circular-motion
UNIVERSAL GRAVITATION
WHAT HAPPENED TO F = M*G?
F = mg is incomplete in a sense because it does not take into account the strength of the gravitational field of a planet and how the gravitational strength will vary depending on the radius.
FG = (G*M1*M2)/R^2
You can find the force of gravity acting on an object by multiplying the gravitational constant by the masses of the two objects in relation to each other and dividing by the radius squared. This would explain why an object in space feels no gravity. Because the radius is increasingly high, the force of gravity approaches zero.
LAW OF UNIVERSAL GRAVITATION
The force of gravity is directly proportional to the masses of each body and inversely proportional to the square of the distance between them.
KEPLER'S LAWS OF PLANETARY MOTION
1ST LAW OF ORBITS
All planets move about the sun in elliptical orbits, having the Sun as one of the foci.
LAW OF AREAS
A planet's speed in orbit changes with distance from the sun so that a planet sweeps out equal areas in equal time.
LAW OF PERIODS
The square of the period of any planet is directly proportional to the cube of the semimajor axis.
