WAAP

Question 1

base unit of mass

Answer 1

kilogram - kg

Question 2

base unit of length

Answer 2

metre - m

Question 3

base unit of time

Answer 3

seconds - s

Question 4

base unit of temperature

Answer 4

kelvin - k

Question 5

base unit of electrical current

Answer 5

ampere - A

Question 6

base unit of amount of substance

Answer 6

moles - mol

Question 7

T

Answer 7

tera - 10^12

Question 8

G

Answer 8

giga - 10^9

Question 9

M

Answer 9

mega - 10^6

Question 10

k

Answer 10

kilo - 10^3

Question 11

d

Answer 11

deci - 10^-1

Question 12

c

Answer 12

centi - 10^-2

Question 13

m

Answer 13

milli - 10^-3

Question 14

µ

Answer 14

micro - 10^-6

Question 15

n

Answer 15

nano - 10^-9

Question 16

p

Answer 16

pico - 10^-12

Question 17

Derive Hz

Answer 17

Frequency = 1/time
f=1/t
f=1/s=s^-1

Question 18

Derive Pa (pascal)

Answer 18

pressure = force/area
p=F/A
p=ma/A
p=kg m s^-2/m^2
p=kg m^-1 s^-2

Question 19

Derive J (joule)

Answer 19

work done = forcedistance
W=fd
W=mad
W=kg m s^-2 m
W=kg m^2 s^-2
——————————————————————-
Kinetic energy = 1/2mass*velocity^2
E=0.5mv^2
E= kg (m s^-1)^2
E= kg m^2 s^-2

Question 20

what are homogenous equations

Answer 20

units on both sides of the equation are equal

Question 21

prove that v^2 = u^2 +2as is homogenous

Answer 21

v^2
=(ms^-1)^2
=m^2 s^-2
—————————————————————-
u^2 + 2as
=(ms^-1)^2 + ms^-2 m
=m^2 s^-2 + m^2 s^-2
=m^2 s^-2

Question 22

What is accuracy

Answer 22

accuracy is how close to the real value

Question 23

What is precision

Answer 23

precision is how close the results are together

Question 24

What are random errors

Answer 24

random errors are unpredictable and occurs by chance

Question 25

How do random errors typically affect a graph

Answer 25

random errors typically affect the gradient of the graph

Question 26

how to reduce the effect of random errors

Answer 26

to reduce the effect of random errors, take multiple measurements

Question 27

What are systematic errors

Answer 27

Systematic errors happens consistently and will affect all measurements by the same amount

Question 28

how do systematic errors affect a graph

Answer 28

systematic errors will not affect the gradient of the graph but will displace the line

Question 29

examples of systematic errors

Answer 29

-zero error
-parallax

Question 30

what is the absolute uncertainty of a DATA SET

Answer 30

half the range of the data set

Question 31

What is the absolute uncertainty of a device

Answer 31

the absolute uncertainty is the smallest scale reading of that instrument

Question 32

how to work out percentage uncertainty

Answer 32

percentage uncertainty

(absolute uncertainty/value)*100

Question 33

what uncertainty to use when data is added or subtracted

Answer 33

add absolute uncertainty

Question 34

what uncertainty to use when data is multiplied or divided

Answer 34

add percentage uncertainties

Question 35

What to do with the uncertainty when data is raised to the power of n

Answer 35

Multiply the percentage uncertainty by the power

Question 36

What does the error bar on the graph tell us

Answer 36

the error bar shows the absolute uncertainty

Question 37

How to draw the line of worst acceptable fit

Answer 37

draw a line from the bottom of the first error bar and the top of the last error bar or vice versa

Question 38

how to work out percentage uncertainty in the gradient

Answer 38

percentage uncertainty of gradient

[ (best gradient-worst gradient)/best gradient ] * 100

Question 39

derive N (newton)

Answer 39

force (N) = mass (kg) * acceleration (ms^-2)
=kg m s^-2

Question 40

derive W (watt)

Answer 40

power (W) =work (or energy) (J) / time (s)
=J s^-1
———————————————————–
J = N * m
J = kg * m * s^-2 * m
J = kg m^2 s^-2
———————————————————–
W = kg m^2 s^-2 s^-1
=kg m^2 s^-3

Question 41

derive C (coulomb)

Answer 41

charge (C) = current (I) * time (s)
=As

Question 42

derive V (volt)

Answer 42

potential difference (V) = energy (J) / charge (C)
=kg m^2 s^-2 / As
=kg m^2 A^-1 s^-3

Question 43

derive Ω (ohm)

Answer 43

resistance (Ω) = p.d. (V) / I (A)
=kg m^2 A^-1 s^-3 / A
=kg m^2 A^-2 s^-3