Chapter 1: Physical quantities, units, and measurements

Question 1

Define physical quantity

Answer 1

a physical quantity is a quantity that can be measures. It consists of a numerical magnitude and a unit

Question 2

Name all 6 base quantities

Answer 2

length
mass
time
electric current
thermodynamic temperature
amount of substance

Question 3

What is the SI unit of length?

Answer 3

metre (m)

Question 4

what is the SI unit of mass?

Answer 4

kilogram (kg)

Question 5

what is the SI unit of time?

Answer 5

second (s)

Question 6

the SI unit of electric current is ampere (A) true or false?

Answer 6

True

Question 7

What is the SI unit for thermodynamic temperature?

Answer 7

kelvin (K)

Question 8

(BONUS) SI unit of amount of substance is mole (mol) true or false?

Answer 8

true

Question 9

Recall all prefixes in order of descending power

Answer 9

tera (T) 10¹²
giga (G) 10⁹
mega (M) 10⁶
kilo (k) 10³
deci (d) 10‐¹
centi (c) 10‐²
milli (m) 10‐³
micro (mew) 10‐⁶
nano (n) 10‐⁹

Question 10

What is the factor of tera?

Answer 10

10¹²

Question 11

What is the factor of giga?

Answer 11

10⁹

Question 12

What is the factor of mega?

Answer 12

10⁶

Question 13

What is the factor of kilo?

Answer 13

10³

Question 14

The factor of micro is 10 to the power of negative 9 true or false?

Answer 14

False. The factor of micro is 10 to the power of negative 6.

Question 15

What is the factor of deci?

Answer 15

10 to the power of negative 1

Question 16

What is the factor of centi

Answer 16

10 to the power of negative 2

Question 17

The factor of milli is 10 to the power of negative 3 true or false?

Answer 17

TRUE

Question 18

Factor of nano?

Answer 18

10 to the power of negative 9

Question 19

What is the tail of a digital caliper used for?

Answer 19

To measure the depth of an object

Question 20

What is the function of a zero button?

Answer 20

To reset the the displayed length back to zero (for digital calipers/micrometer screw gauge)

Question 21

Which part of a digital caliper is used to measure the internal diameter of an object?

Answer 21

The inside jaws

Question 22

What are the outside jaws of a digital caliper used for?

Answer 22

To measure the external diameter/width of an object

Question 23

What is the function of a locking screw (digital caliper)

Answer 23

To ensure that the jaws do not move apart.

Question 24

What is a ratchet? (micrometer screw gauge)

Answer 24

can be turned to adjust the spindle so that the spindle is in contact with the object

Question 25

Two ways to **avoid** *errors of measurement* are?

Answer 25

Position eyes such that line of sight is perpendicular/directly above rule to avoid parallax error Take several readings and calculate the average to minimise errors.

Question 26

What is a **pendulum**?

Answer 26

Can be used to measure time Consists of a heave object (bob), attached to one end of a string When a pendulum swings freely, it moves to and fro in regular intervals. Each complete to and fro motion is an oscillation

Question 27

State what is meant by a **period**

Answer 27

A period is the time taken for one complete oscillation

Question 28

What are **scalar** and **vector** quantities?

Answer 28

SCALAR QUANTITIES are physical quantities that have *only magnitude* VECTOR QUANTITIES are physical quantities that have both *magnitude and direction*

Question 29

Recall all **scalar** quantities

Answer 29

Distance Speed Mass Energy Time

Question 30

Recall all **vector** quantities

Answer 30

Displacement Velocity Acceleration Force Weight

Question 31

*Define* the word **speed**

Answer 31

SPEED is the distance moved per unit time It's SI unit is metre per second (m/s)

Question 32

What is the formula to find speed?

Answer 32

distance ➗️ time taken

Question 33

*Define* the term **Velocity**

Answer 33

VELOCITY is the rate of change of displacement. It's SI Unit is metre per second (m/s)

Question 34

State the **formula** for *velocity*

Answer 34

displacement ➗️ time taken