Key Equations

Question 1

*Strength of a magnetic field

Answer 1

Magnetic Field=1 tesla=B= N/Am= µV/2rR

Question 2

Circuits (voltage)

Answer 2

Voltage= V=IR

Question 3

Parallel plates equation

Answer 3

Voltage=V= Ed

Question 4

• Voltage (3 eqns)

Answer 4

Voltage=V= Kq/R=w/q=Q/c

Question 5

*Power (circuits)

Answer 5

Power=watts=P=IV

Question 6

*Power (relating to work and energy)

Answer 6

Power= ∆W/∆T= E/T

Question 7

Force between two charges (if one on either side, do forces separately and add if same direction, subtract if opposite)

Answer 7

Force=F=KQq/r^2

Question 8

Pendulum KE, PE

Answer 8

KE=1/2mv^2 PE= U= mgh

Question 9

Pendulum angular momentum

Answer 9

w=√g/L

Question 10

Spring PE and Work

Answer 10

PE=W=1/2kx^2 (k is spring constant)

Question 11

Spring angular frequency

Answer 11

w=√k/m=2πf

Question 12

Force due to a spring (i.e. can be used when considering oscillation)

Answer 12

F=-kx

Question 13

Force on a moving charge

Answer 13

F=qvBsinθ *parallel F=0

Question 14

Force due to current carrying wire

Answer 14

F=ILBsinθ *parallel F=0

Question 15

Capacitance between two parallel plates (i.e. have voltage and charge)

Answer 15

C=q/V *q=charge on plate

Question 16

Two parallel plates, same area, capacitance?

Answer 16

C=ε (A/d) *ε= electric constant, d=distance between places

Question 17

*Guage Pressure (2 eqns)

Answer 17

P=F/A=pgh *h=height of fluid

Question 18

Pressure concerning gas

Answer 18

PV=nRT R= .082 atmL/mole*K

Question 19

General Work

Answer 19

W=Fd=Fdcosθ

Question 20

Work done relating to electricity

Answer 20

W=qV *V=potential aka voltage

Question 21

Current (circuits)

Answer 21

I=Q/T Units: Amps=C/s

Question 22

*Impulse

Answer 22

J=∆p (∆momentum)=F∆t

Question 23

Momentum

Answer 23

p=mv

Question 24

*Specific Gravity

Answer 24

p substance/p water (p=density)

Question 25

*Specific Heat

Answer 25

Q=MC∆T

Question 26

Buoyancy Force

Answer 26

Fbuo= weight of object in empty space − weight of object immersed in fluid F=Vsubmerged*g*p fluid (p=density)

Question 27

*Floating Force

Answer 27

Fbuoyancy=Fgravity F=mg

Question 28

Gibbs Free Energy redox reaction

Answer 28

∆G=-nFEcell

Question 29

General Gibbs Free energy (spontaneity, enthalpy etc.)

Answer 29

∆G=∆H-T∆S

Question 30

Torque

Answer 30

t=Fr=Frsinθ (r=displacement vetor, F=force vector)

Question 31

Free fall

Answer 31

H=1/2 gt^2

Question 32

*Mirror equation

Answer 32

1/f=2/r=1/o+1/i

Question 33

Magnification

Answer 33

M=-i/o and Object d / Image d=Object h / Image h

Question 34

Velocity of light in a medium

Answer 34

V=c/n (c=speed of light, n=index of refraction)

Question 35

*Bernoulli's

Answer 35

P+1/2pv^2+pgh=constant

Question 36

Electric Potential Energy

Answer 36

U=q∆V=qEd (u in Joules)

Question 37

Volume expansion

Answer 37

∆v=BV∆T (B=coefficient of volume expansion)

Question 38

Snell's Law of Refraction

Answer 38

n1(sinθ)=n2(sinα) (θ is entry, and α is exit, always measure angle from vertical line)

Question 39

Gravitational Force

Answer 39

F=Gm1m2/r^2

Question 40

*Acceleration due to Gravity

Answer 40

mg=F=Gm1m2/R g=Gmearth/r^2

Question 41

Electric Field

Answer 41

E=kq/r^2=F/Q

Question 42

Speed of light

Answer 42

C=fλ

Question 43

Centripetal force

Answer 43

Fc=mv^2/r

Question 44

Internal Energy

Answer 44

∆U=Q-W

Question 45

*Change in Boiling Point

Answer 45

∆Tb=Kb*m*i (molality & ions/mole)

Question 46

Resistance in a wire

Answer 46

R=PL/A (P=constant, Length and Area)

Question 47

*Molality

Answer 47

molality=m or b= n solute/ m solvent

Question 48

Faradays constant

Answer 48

magnitude of electric charge per mole of gas = 96,500 C/mole e-

Question 49

Density of H2O

Answer 49

= 1000 kg/m^3

Question 50

Specific heat of H2O

Answer 50

= 1 cal/g degree C=4.2 J/g degree C

Question 51

Volume of 1g H2O

Answer 51

= 1cm^3=1ml

Question 52

R (gas constant)

Answer 52

= 8.3 J/mol K

Question 53

atm-> torr

Answer 53

1 atm=760 torr=760 mm Hg

Question 54

Avogadros

Answer 54

= 6.022*10^23

Question 55

Velocity of Sound

Answer 55

= 330 m/s

Question 56

When you have velocity, distance, trying to solve for acceleration/decellaration

Answer 56

Vf^2=Vo^2+2ax (final velocity is 0 if coming to a rest)

Question 57

When you only care about velocity & distance in X direction

Answer 57

x=Voxdirection*t *remember time is only until max height

Question 58

When considering Y-direction velocity and time

Answer 58

Vy=Voydirection+at *remember time is only until max height

Question 59

Find distance to deceleration

Answer 59

∆X=average V*t (average V= Vo+V/2)

Question 60

Find frequency of photon given total energy & emitted photons per second

Answer 60

E=hf *solve for energy per 1 photon, then find f

Question 61

How do you increase energy?

Answer 61

Decrease wavelength or increase frequency

Question 62

Period of mass on the end of a spring

Answer 62

T= 2pi√m/k (period if the time for one cycle)

Question 63

Frequency vs. Period

Answer 63

Frequency is rate of cycles per second. Period is time for full cycle 1/T=f

Question 64

Acceleration on another planet

Answer 64

F=GmM/R^2 then use a=F/m to get a=GM/R^2 (the big M is the mass of the planet)

Question 65

Calculate heat of reaction from average bond enthalpies

Answer 65

∆H=∆H Bonds Broken- ∆H Bonds Formed

Question 66

Calculate concentration from pH

Answer 66

[H+]=10^-x (pH=x)

Question 67

Electric Potential

Answer 67

Potential Energy/q=kqQ/r/q=kQ/r (units J/C)

Question 68

Work required to to bring charge closer to same-charged particle

Answer 68

Work required=∆PE=q∆V