definitions

Question 1

vector

Answer 1

a physical quantity that has both magnitude and direction

Question 2

resultant

Answer 2

the single vector which has the same effect as all the component vectors together would have

Question 3

maximum resultant

Answer 3

obtained when two vectors act in the same direction

Question 4

minimum resultant

Answer 4

obtained when 2 vectors act in opposite directions

Question 5

distance

Answer 5

length of the path actually taken

Question 6

displacement

Answer 6

a body’s change in position

Question 7

speed

Answer 7

rate of change of distance moved

Question 8

instantaneous speed

Answer 8

speed at a particular moment

Question 9

velocity

Answer 9

rate of change of position

Question 10

instantaneous velocity

Answer 10

the velocity at a particular moment

Question 11

acceleration

Answer 11

the rate of change of velocity

Question 12

pure substance

Answer 12

consists of one type of substance only and are made up either of elements or compounds, have a constant composition

Question 13

element

Answer 13

a substance that cannot be broken down into simpler substances. made up of only one type of atom

Question 14

compound

Answer 14

formed when two or more pure substances combine chemically with each other in a fixed ratio

Question 15

mixture

Answer 15

combination of two or more substances in which the substances retain their individual properties. can be present in any ratio

Question 16

homogeneous mixture

Answer 16

a mixture in which the composition of the mixture is the same throughout and consists of two or more substances in the same phase

Question 17

heterogeneous mixture

Answer 17

a mixture in which the composition of the mixture is not uniform

Question 18

temperature

Answer 18

an object is proportional to the average kinetic energy of its particles

Question 19

melting point

Answer 19

temperature at which a solid changes phase to become a liquid

Question 20

freezing point

Answer 20

temperature at which a liquid changes phase to become a solid

Question 21

boiling point

Answer 21

temperature in which a liquid changes phase to become a gas, or a gas changes into a liquid

Question 22

evaporation

Answer 22

takes place at any temperature at surface only

Question 23

scalar

Answer 23

a physical quantity which has a magnitude only

Question 24

sublimation

Answer 24

when a substance changes straight from a solif to a gas

Question 25

atomic number

Answer 25

the number of protons in an atom

Question 26

mass number

Answer 26

the number of protons plus neutrons in an atom

Question 27

isotopes

Answer 27

atoms of the same element which have different mass numbers. they have the same nuber of protons in the nucleous, but a different number of neutrons

Question 28

ion

Answer 28

a charged atom

Question 29

cation

Answer 29

a positively charged atom because it has lost an electron

Question 30

anion

Answer 30

a negatively charged atom because it has gained an electron