Chapter 2: Work and Energy Flashcards
Kinetic energy= SPEED
Kinetic energy is the energy of motion so anytime and object that has a mass and is moving with some SPEED it will have an associated amount of kinetic energy.
K=1/2 mv2 where v is SPEED
Measured in J joules kg*m2/s2
Falling objects have kinetic energy. Fluids flowing can have kinetic energy measured using Bernoulli‘s equation. Object sliding down an inclined plane game kinetic energy other speeds increase down the ramp. 
Potential energy: gravitational and elastic
Potential energy refers to the potential to do work or an objects given position in space.
There are two forms of potential energy gravitational potential energy and elastic potential energy . 
Gravitational potential energy. U=mgh, where g refers to gravity 9.8 m/s, and h refers to height in relevance to object and surface. Note anything below ground level is negative.
Elastic potential energy. U=1/2 kx2 where k is spring constant and x is displacement from equilibrium
Total mechanical energy: Conservative energy and Non conservative energy
Total mechanical energies referred to the sum of objects potential and kinetic energies it is the first law of thermodynamics.
Conservative energy deals with force of gravity electrostatic forces which conserves mechanical energy. They are path independent and do not dissipate energy.
Conservative energy equation: Change in E= change in U (potential) + Change in K =0 zero!
Nonconservative forces such as friction air resistant or visscuit drag our present, total mechanical energy is not conserved. Mechanical energy is dissipated and it is path dependent the longer the distance traveled the larger amount of energy dissipated.
Nonconservative energy equation: Work=  Change in E= change in U (potential) + Change in K
Work: force and displacement, pressure and volume
Work is not energy but the process in which energy is transferred to a system. There are two ways that energy can be transferred that is work and heat.
Force and displacement: Definition of work (mechanical): W = F · d = Fd cos θ, where d is displacement, cosine angle between the applied force factor and displacement vector
Pressure and volume: gas system with cylinder and piston Definition of work (isobaric gas–piston system): W = PΔV
Area=1/2 Change in P * Change in V
Isobaric means pressure is constant. Isovolumetric or Isochoric means volume is constant which means no work is being done. 
Power
Power is the rate at which energy is being transferred or the rate of work being done. Power can be seen used in circuits resistors and capacitors. Power is measured in watts which is joules/ second
P=Works/time= Change in energy/ time 
The equation for electric power is: P=IV,
Where the I stands for current, and the V is electrical potential difference or voltage
Work energy theorem: calculating work using kinetic energy
This is an expression of the relationship between work and energy. This relationship is important because you can calculate work without knowing the magnitude of the forces acting on the object or the displacement through which the forces act. previously we have seen work equal to force times displacement, however work is also equal to the change in kinetic energy: or final kinetic energy minus additional kinetic energy. Remember kinetic energy is 1/2 mass times speed squared.
Work–Energy theorem: Wnet = ΔK = Kf – Ki
