1 - Measurements and units

Question 1

What is a physical quantity made of?

Answer 1

A number and a unit

Question 2

What should be included in the stages of a calculation?

Answer 2

Units

Question 3

What is scientific notation (standard form)?

Answer 3

A way of writing numbers using a decimal number multiplied by a power of 10 (eg: 3.20 * 10^5)

Question 4

What are SI units?

Answer 4

A system of units used by most scientists

Question 5

What are some SI base units for different categories?

Answer 5

Mass - kilogram; time - second; length - metre; electric current - ampere; temperature - kelvin

Question 6

What is mass and its properties?

Answer 6

Measure of quantity of matter in object, greater the mass, greater the gravitational attraction of Earth on it and object resists changing speed or direction more

Question 7

How is 1 metre defined?

Answer 7

Distance travelled by light in a vacuum in 1 / 299,792,458th of a second

Question 8

What are the different prefixes which can be added to units to change their values and how?

Answer 8

G (giga) - 10^9; M (mega) - 10^6, k (kilo) - 10^3; d (deci) - 10^-1; c (centi) - 10^-2; m (milli) - 10^-3; µ (micro) - 10^-6; n (nano) - 10^-9

Question 9

What are ways of measuring length?

Answer 9

Using a rule, using calipers if rule can’t be placed right next to object, use tape for lengths of several metres, use laser tape measure

Question 10

What are ways of measuring time and what needs to be done?

Answer 10

Stopclock, stopwatch, with analogue or digital display, account for zero error

Question 11

How much is a litre (L)?

Answer 11

1 L = 1000 mL (millilitre), 1000 cm^3 (centimetre cubed), 1 dm^3 (decimetre cubed)

Question 12

What is the density (kg/m^3) of air?

Answer 12

1.3

Question 13

What is the density (kg/m^3) of expanded polystyrene?

Answer 13

14

Question 14

What is the density (kg/m^3) of wood (beech)?

Answer 14

750

Question 15

What is the density (kg/m^3) of petrol?

Answer 15

800

Question 16

What is the density (kg/m^3) of ice (0℃)?

Answer 16

920

Question 17

What is the density (kg/m^3) of polythene?

Answer 17

950

Question 18

What is the density (kg/m^3) of water (4℃)?

Answer 18

1000

Question 19

What is the density (kg/m^3) of concrete?

Answer 19

2,400

Question 20

What is the density (kg/m^3) of glass (varies)?

Answer 20

2,500

Question 21

What is the density (kg/m^3) of granite?

Answer 21

2,700

Question 22

What is the density (kg/m^3) of aluminium?

Answer 22

2,700

Question 23

What is the density (kg/m^3) of steel (stainless)?

Answer 23

7,800

Question 24

What is the density (kg/m^3) of copper?

Answer 24

8,900

Question 25

What is the density (kg/m^3) of lead?

Answer 25

11,400

Question 26

What is the density (kg/m^3) of mercury?

Answer 26

13,600

Question 27

What is the density (kg/m^3) of gold?

Answer 27

19,300

Question 28

What is the density (kg/m^3) of platinum?

Answer 28

21,500

Question 29

What is the density (kg/m^3) of osmium?

Answer 29

22,600

Question 30

What are the ways of measuring volume?

Answer 30

Measuring cylinder, calculation, see rise in liquid in measuring cylinder, displacement can

Question 31

What are the ways of measuring density?

Answer 31

Calculation, hydrometer (for liquids)

Question 32

What is the average density of the Earth?

Answer 32

5520 kg/m^3

Question 33

What is the average density of Jupiter?

Answer 33

1330 kg/m^3

Question 34

What is the formula for speed?

Answer 34

Average speed (v) = distance moved (s) / time taken (t)

Question 35

What is the SI unit of speed?

Answer 35

m/s

Question 36

What is velocity and its difference from speed?

Answer 36

Velocity means the speed of something and its direction of travel

Question 37

What are vectors?

Answer 37

Quantities with a magnitude and a direction

Question 38

What is the formula for acceleration?

Answer 38

Average acceleration (a) = change in velocity (Δv) / time taken (Δt)

Question 39

What is a negative acceleration called?

Answer 39

Deceleration or retardation

Question 40

What is the SI unit of acceleration?

Answer 40

m / s^2

Question 41

What are important properties of speed-time and distance-time graphs?

Answer 41

On a distance-time graph, the gradient of the line is equal to the speed; on a speed-time graph, the gradient of the line equals acceleration and the area under the line equals the distance travelled

Question 42

What can a ticker-tape timer be used for?