Formulas

Question 1

gauge pressure formula

Answer 1

Pgauge = pgd

Question 2

flow speed and pressure

Answer 2

high flow speed has low pressure

Question 3

ratio of cross sectional area to speed of liquid flow in tubes

Answer 3

A1V1 = A2V2

Question 4

force acting on object moving underwater

Answer 4

Fnet = Fbuoy - mg
Fbuoy = pVg
mg = (p of object x V)g

Question 5

how density changes speed of emerging stream

Answer 5

same speed for all fluid

Question 6

viscosity is not in bernoulli’s equation

Answer 6

no term corresponding to production of heat

Question 7

E = qV
V = (kQ/r - kQ/r)

Answer 7

change in potential energy is same as energy to move charge from one place to another

Question 8

work required to move charge

Answer 8

equal to change in potential energy

if moving from 4cm to 3cm away in a different direction, same as moving from 4cm to 3cm

Question 9

when is electric field or electric potential between charges 0

Answer 9

electric field: halfway between charges

electric potential: never

Question 10

finding electric field vs electric potential between charges

Answer 10

field: find hypotenuse between and multiply by E of one
charge: add both

Question 11

magnitude of force charge would feel due to electric field

Answer 11

F=qE
if finding speed of proton and electron from same location, same q, but mass is different
a = F/m

Question 12

relationship between resistance and capacitance in a network

Answer 12

in a network, energy consumed by resistor network is equal to energy supplied by capacitance
can measure energy consumed by resistors by using formula for capacitance
Q=CV
PE = 1/2QV
PE = 1/2CV^2

Question 13

force felt between 2 charges

Answer 13

F = k q1q2/r^2

Question 14

k

Answer 14

9x10^9

Question 15

SI unit of charge e-

Answer 15

1.6x10^-19 C

Question 16

electric field created by a charge

Answer 16

E = kQ/r^2

Question 17

how charges move in conductor vs insulator

Answer 17

conductor: excess charge moves to opposite side of surface because they repel, no electric field is created and inside E= 0 because they cancel out
insulator: charged Q means it will become polarized

Question 18

current is

Answer 18

Q/t

Question 19

resistance changes depending on

Answer 19

R = pL/A
p: internal resistivity
A: area
L: length

Question 20

power is

Answer 20

I^2R

IV

Question 21

V is

Answer 21

IR
resistance remains constant at varying V
current reverses if V polarity reverses

Question 22

resistors in series

Answer 22

same current

R+R

Question 23

resistors in parallel

Answer 23

same voltage
RR/R+R
current going in + current coming out

Question 24

capacitors in series

Answer 24

same current

CC/C+C

Question 25

capacitors in parallel

Answer 25

same voltage

C+C

Question 26

measuring current or voltage

Answer 26

measure current in series - for internal resistance to be negligible, you want it small
measure voltage in parallel - for internal resistance to be negligible you want it big

Question 27

what a capacitor is and what they’re used for

Answer 27

pair of conductors that hold equal but opposite charge
creates uniform electric field throughout V=Ed
stores electrical potential energy

Question 28

charge on a capacitor, how to change capacitance

Answer 28

Q=CV
C=EA/d
C only changes with change in area, distance, or E: permitivity of free space

Question 29

how is Q=CV affected by dielectric if connected to a battery

Answer 29

Q increases to keep V at same level despite dielectric, increasing C

Question 30

how is Q=CV affected by dielectric if not connected to a battery

Answer 30

becomes polarized to lower V, which then increases C

Question 31

what happens to Q, C, V, electric field, and potential energy if capacitor is charged by battery, disconnected, and dielectric inserted

Answer 31

Q same cuz on battery
C increases w dielectric so V goes down
with V=Ed electric field decreases
with PE=1/2QV PE also decreases
where does PE go? some get stored as induced dipoles, some KE you feel when plates pull on dielectric

Question 32

what happens to Q, C, V, electric field, and potential energy if capacitor is charged, and dielectric is inserted while connected

Answer 32

V same cuz battery
C increases, so Q increases
in V=Ed, E doesn’t change
in PE = 1/2QV, PE increases

Question 33

dielectric breakdown

Answer 33

when electric field is so strong that dielectric becomes ionized and electrons flow