equations i need to learn

Question 1

efficiency

Answer 1

useful energy in /total energy out

Question 2

kinetic energy lost is

Answer 2

potential energy gain

Question 3

moment of a couple

Answer 3

magnitude of one force x perpendicular distance between lines of action

Question 4

young modulus (in symbols)

Answer 4

(FL) / ( A x extension)

Question 5

energy stored (materials)

Answer 5

1/2 k (extension squared)

Question 6

area (with radius and diameter)

Answer 6

• pi x r^2
  -( pi x d ^2) / 4

Question 7

emf

Answer 7

Ir + v

Question 8

work done (current time and voltage)

Answer 8

ItV

Question 9

intensity

Answer 9

power/area

Question 10

phase difference (in radians)

Answer 10

(2pi x path difference ) / wavelength

Question 11

n2/n1 = c1/c2

Answer 11

c1/c2 = wavelength1/wavelength2 = sin01 / sin02

Question 12

surface area of a sphere

Answer 12

4pir^2

Question 13

1 ev

Answer 13

1.6 x 10 ^ -19

Question 14

hf0

Answer 14

work function

Question 15

E (particles)

Answer 15

mc^2

Question 16

a is proportional (shm)

Answer 16

-x

Question 17

E total = Ep max = Ek max (shm)

Answer 17

1/2 m w^2 A^2

Question 18

N (number of particles)

Answer 18

n Na
- number of moles (n)

Question 19

molar mass

Answer 19

total mass/ n

Question 20

molecular mass

Answer 20

• total mass / N
• molar mass/ Na

Question 21

mass per second

Answer 21

density x volume per sec

Question 22

volume per sec

Answer 22

speed x cross-sectional area

Question 23

Ep (gravitational)

Answer 23

-GMm/r

Question 24

T^2 is proportinal to (orbit)

Answer 24

r^3

Question 25

GMm/r^2 (orbit)

Answer 25

mv^2 / r

Question 26

escape velocity

Answer 26

• square root of (2GM/R)
• square root of (2gr)

Question 27

Ek (orbit)

Answer 27

GMm/2r

Question 28

Etotal (orbit)

Answer 28

-GMm/2r

Question 29

work done (if pressure is constant)

Answer 29

p x change in V

Question 30

pressure (in density)

Answer 30

1/3 x density x crms^2

Question 31

electric energy

Answer 31

power x time

Question 32

work done

Answer 32

QV
-change in v

Question 33

F (electric fields)

Answer 33

QV/d

Question 34

Ep (electric fields)

Answer 34

Qq/4pi e0 r

Question 35

capacitors in series

Answer 35

1/c1 + 1/c2 (like resistors in parallel)

Question 36

capacitors in parallel

Answer 36

c1 + c2 (like resistors in series)

Question 37

r (magnetic )

Answer 37

mv/BQ

Question 38

emax (emf in magnetic)

Answer 38

BANw
-max flux linkage x w

Question 39

Paverage

Answer 39

Irms Vrms

Question 40

if 100% efficient (magnetic field)

Answer 40

Ip/Is
-p is primary coil
-s is secondary coil

Question 41

e (emf in magnetic)

Answer 41

BLv

Question 42

total binding energy

Answer 42

binding energy per nucleon x number of nucleons

Question 43

lnN (nuclear)

Answer 43

(-decay constant x t) + lnN0

Question 44

binding energy

Answer 44

mass defect x c^2

Question 45

m (special relativity)

Answer 45

m0 / sqaure root (1 - v^2/c^2)

Question 46

Ek (special relativity)

Answer 46

mc^2 - m0c^2