Physics Lab

2008-Energy

Linear WorkThe act of exerting a force through a

distance in the direction of the force (constant)

W = Fx cos F = Force x = Displacement cos = angle w.r.t. Force

Rotational WorkThe act of exerting a torque through an

angular displacement (fixed Axis) W =

= Torque = angular Displacement

Work Done by PressureThe act of maintaining a pressure

through a volume change (Constant Pressure)

W = P V W = Work, P = Pressure V = change of Volume

Work done by an Electric FieldThe act of moving an electric charge

within an electric field (Constant Field)W = E q x

E = Electric Field Strength, q = electric charge, x = Displacement

Linear Kinetic EnergyThe ability to do work because of

linear motionKE = 0.5 m v2

m= mass V= linear velocity

Rotational Kinetic EnergyThe ability to do work because of

rotational motion. (fixed axis)KErot = 0.5 I 2

I = moment of Inertia = angular velocity

Potential EnergyThe ability to do work because of

position within a force field

Gravitational Potential EnergyThe ability to do work because of

position within the gravitational force field

PE = mgh m = mass g = gravity (9.8 m/sec2) h = height w.r.t reference

Spring Potential EnergyThe ability to do work because of

elongation or compression of a springUs = .5 k s2

k = spring constant s = amount spring compressed or

extended

Electric Capacitor Potential EnergyThe ability to do work because of

electric charges stored in an Electric Force field

Uq = .5 q2/C q = charge C = capacitance

PressurePotential Energy per unit volume within

a fluid (liquid and/or gas/vapor)P = F/A

P = pressure F = force A = area

Ideal Gas Law Relationship between energy stored in Ideal

gas and its temperature PV = nRT

P = pressure V = volume n = number of moles of gas R = the energy to change the temperature of one

mole of gas by one Kelvin T=temperature in Kelvin

PowerThe rate at which work is done or

energy is transformed (used or generated)

P = W/T P = Power W = Work T = time to do work

Linear PowerThe rate at which work is done during

linear motionP = Fv

P = Power F = Force v = velocity

Rotational PowerThe rate at which work is done during

rotational motion (Fixed Axis)P =

P = Power = Torque = angular velocity

Electrical PowerThe rate at which electrical energy is

generated or transformed to other energy

P = VI P = Power V = Electrical Potential (Volts) I = Current (Amps)

Ohmic HeatingThe rate at which electrical energy is

transformed into heatP = I2R

P = Power I = Current (Amps) R = Resistance (Ohms)

Fluid PowerThe rate at which a liquid fluid does

work, (hydraulic)P = pv

P = Power p = pressure v = volume flow rate

EfficiencyThe ratio of usable energy resulting

from an energy conversion to the total energy supplied for the conversion.

Efficiency of Work

e = Wout/Win

Wout = useful work out

Win = Total work input

Efficiency of Power

e = Pout/Pin

Pout = useful power out

Pin = Total power input

Efficiency of Energy Conversion

E= Eout/Ein

Eout = Useful Energy out

Ein = Total Energy Input

Other NotesAny other equations the students must

use must be provided by Event supervisor

All answers must be in SI Units ( Newton, Joule, Watt, Kilogram, meter, and second)

All answers must have the proper number of significant figures

Students may bring non-programmable calculator