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.
MECHANICAL ENERGY
Mechanical Energy is the Kinetic Energy in a System plus the Potential Energy. This always remains constant.
CONSERVATION OF ENERGY
Conservation of Energy
The Law of the Conservation of Energy states that energy is never created and it is never destroyed. It can only be transferred from one type of energy to another, so it is never lost from the whole system. This means that all the energy present in this world today was present at the creation of the universe billions of years ago.
ENERGY CALCULATIONS
As mentioned before, there are many types of energy and different formulas to calculate the energy present in these "storage accounts".
ELASTIC POTENTIAL ENERGY
The formula for Elastic Potential Energy is E = 1/2*kx^2, where k represents the spring constant and x represents the compression of the spring. This formula can also be used to find the spring constant when given the displacement of compression and Energy produced. It can also be used to find how much spring has been compressed given the spring constant and the energy produced. This equation is extremely useful for us because, in many problems, a spring is used to launch an object and this formula can be essential in finding the maximum distance that object traveled.
GRAVITATIONAL POTENTIAL ENERGY
Gravitational Potential Energy can be used to find how much work it takes to lift an object. The formula for this would be the Force times the height, which by translation means mass * gravity * height or mgh. This equation is incredibly useful for us because the Earth is involved in the majority of systems and this equation is required to find the gravitational energy on that object at any given point
KINETIC ENERGY
Kinetic Energy can be used to find the energy that an object has when it is moving. The formula for kinetic energy is 1/2 * mv^2, where m represents the mass of the object in question and v is the velocity. This equation is really useful because if the final position in a system or the initial position involves an object in motion, using this formula and the law of conservation of energy, you will be able to calculate the amount of energy that will be stored in other accounts and using those respective formulas, other information about the system can be found like spring constant, maximum height, and so forth.
https://www.proprofs.com/quiz-school/story.php?title=conservation-energy
ENERGY TRANSFER
WORKING (W)
Working is when the Energy is transferred in or out of the system by exerting an external push or pull on a system. This means something outside the system has to act on it.
HEATING (Q)
A heating transfer is when the energy is transferred in or out of the system due to temperature. Temperature is the average amount of kinetic energy in an object. A temperature difference between the system and its surroundings would cause a Q energy transfer
RADIATING (R)
A radiating energy transfer is when the matter loses or gains energy due to the influence of light. Losing energy in this situation would be the radiating of light, but by absorbing light you would be getting energy. For example the sun and humans.
https://www.goodhousekeeping.com/appliances/microwave-reviews/g2049/countertop-microwave-reviews/
POWER
POWER (WATTS)
Power is the rate of the transfer of energy, acting over some distance. It is measured by dividing work done by change in time.
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.
