Physics Review Unit 6 Work, Power, and Energy

University:
Concordia University Wisconsin
Course:
PHYS 1514 | General Physics I
Academic year:

2019
Views:

400

Pages:

5
Author:

gildnar99xu

Unit 6: Work, Power, and Energy - Work: When a force acts on an object and causes a displacement of the object, it is said that work was done on the object. Work can be expressed by the following equation: Work=(Force)(Displacement). The unit for work is N x M, also known as Joules (J). Work is positive when the component of force and displacement are both in the same direction. Work is negative when the component of force and displacement are in opposite directions. - Power: The rate at which work is done. Power can be expressed by the following equation: P= W/T. The unit for power is Joules/Second= Watt= Horsepower. - 1 Horsepower=735.5 Watts - Conservation of Energy: Energy can be neither created nor destroyed. Energy can only be transferred or transformed. When work is done on an object, energy is transferred or transformed. - Gravitational Potential Energy: When doing work against gravity, energy is stored in the gravitational field. Potential energy is an energy difference from a reference point, such as a surface below an object. - - As an object begins to fall, its potential energy decreases due to its loss in height. The lost potential energy becomes kinetic energy. - Kinetic energy is the energy of motion. It describes the work needed to change the velocity of the object. - - Conservation of Mechanical Energy: The total energy in a system or object does not change. The energy in a system is only transformed into other forms. Spring Potential Energy - Springs contain potential energy if it’s stretched or compressed from its resting form. In order to stretch or compress a spring, work must be done. - Waves - A disturbance that moves through a medium causing a transfer of energy from one place to another. The different types of waves are transverse waves and longitudinal waves. - Transverse waves: A wave where the particles in the medium move in a direction that is perpendicular to the direction that the wave moves in. - - - Longitudinal waves: A wave where the particles in the medium move in a parallel direction as the direction of the wave. - Reflection of Waves: A wave “bounces back” to its original medium as a result of its change in direction of the wave front after striking a medium boundary. - - Refraction of Waves: A wave becomes distorted when passing from one medium to another. The speed and wavelength of refracted waves may alter. However, the frequency remains the same. - - Diffraction: Occurs as a result of the bending of waves around a barrier. -