Physics CT2

Question 1

Define resultant force

Answer 1

overall force on an object

Question 2

define balanced forces

Answer 2

‘cancel’ each other out, giving a resultant force of zero

Question 3

define newton’s first law

Answer 3

an object will only accelerate if there is a non-zero resultant force acting on it

Question 4

when does newtons first law only work

Answer 4

when there are balanced forces

Question 5

what will happen to the object if it is already moving and the speeding up force and slowing down force are balanced

Answer 5

the object would still move at a constant speed

Question 6

define mass

Answer 6

a measure of how much matter there is in an object

Question 7

what is mass measured in

Answer 7

kg

Question 8

is mass a vector or scalar

Answer 8

scalar

Question 9

define weight

Answer 9

a force, which has the mass and the gravitational field strength

Question 10

what is weight measured in

Answer 10

N

Question 11

is weight vector or scalar

Answer 11

vector

Question 12

how to calculate weight

Answer 12

mass x gravity

Question 13

define terminal velocity

Answer 13

the weight of a falling object is balanced at terminal velocity by the drag force/air resistance

Question 14

What is newton’s second law

Answer 14

if there are no forces acting on an object, it won’t accelerate

Question 15

how to calculate the force

Answer 15

mass x acceleration

Question 16

What happens to the acceleration if the mass increases

Answer 16

it will decrease

Question 17

define inertial mass

Answer 17

the more mass an object has, the more force is needed to accelerate it

Question 18

what are scales called in science

Answer 18

balances

Question 19

what is newtons third law

Answer 19

when two objects interact, there is always a pair of forces present, know as action-reaction forces

Question 20

What are action-reaction forces

Answer 20

always the same size and in opposite directions

Question 21

How to calculate efficiency

Answer 21

useful energy out / total energy in

Question 22

define thermal conductivity

Answer 22

is a measure of how well a material transfers energy

Question 23

what is an example of a high thermal conductivity

Answer 23

Metals - copper

Question 24

what does it mean when an object has a high thermal conductivity

Answer 24

heat travels through it quickly

Question 25

what is an example of a low thermal conductivity

Answer 25

Insulators - plastic/rubber - and still air

Question 26

what does it mean when an object has a low thermal conductivity

Answer 26

heat travels through it slowly

Question 27

what are the 3 heat transfer mechanisms

Answer 27

-conduction -convection -radiation

Question 28

define conduction as a heat transfer mechanism

Answer 28

heat energy moves through the material. vibrating particles in a material pass their energy to their neighbour particles

Question 29

define convection as a heat transfer mechanism

Answer 29

warm fluid rises above colder fluid. The hot fluid moves somewhere else, taking the thermal energy with it

Question 30

define infrared radiation as a heat transfer mechanism

Answer 30

thermal energy is transferred by infrared light. it is the only method that works in a vacum

Question 31

what does infrared mean

Answer 31

before what we can see with our eyes

Question 32

define gravitational potential energy

Answer 32

it depends on the objects mass and height above the ground

Question 33

How to calculate the change in gravitational potential energy

Answer 33

mass x gravity x change in hight

Question 34

define kinetic energy

Answer 34

it depends on an objects speed and mass

Question 35

How to calculate the kinetic energy?

Answer 35

1/2 x m x v(squared)

Question 36

how many grams in a kg

Answer 36

1000

Question 37

what does it mean when energy is conserved

Answer 37

kept the same

Question 38

what unit is gravitation potential energy given in

Answer 38

J

Question 39

How many newtons are in a kN

Answer 39

1000 n