Forces and Motion

Question 1

what’s the difference between speed and velocity?

Answer 1

-speed is how fats your going with no regard too direction
-velocity, however just have the direction e.g/ 30mph north or 060’

Question 2

what is acceleration?

Answer 2

how quickly velocity is changing

Question 3

what is the unit of acceleration?

Answer 3

m/s²

Question 4

what does gradient equal on a velocity/distance graph?

Answer 4

acceleration = vertical/horisontal

Question 5

what is gravity?

Answer 5

the force of attraction between all masses

Question 6

what is the difference between mass and weight?

Answer 6

-mass is the amount of matter in an object
-weight is caused by the pull of gravity

Question 7

why will an object with the same mass have a bigger weight on earth than the moon?

Answer 7

a 1kg mass will weigh less on the moon that it doesn’t on the earth because the force if gravity pulling is less

Question 8

what is weight measured in and how is it measured?

Answer 8

-weight is measured in Newtons (N)
-it’s measured using a newton meter

Question 9

what is mass measured in and how is it measured?

Answer 9

-mass is measured in Kilograms (Kg)
-measured by scales

Question 10

what’s the unit for gravitational field strength?

Answer 10

N/Kg

Question 11

what is gfs on earth?

Answer 11

10

Question 12

what way does gravity/weight act?

Answer 12

close to a planet acts straight downwards

Question 13

what way does reaction force act?

Answer 13

acts perpendicular to a surface and away from it (so if the surface is horizontal the force acts straight upwards)

Question 14

what is thrust?

Answer 14

a push or pull due to an engine or rocket speeding something up

Question 15

what is drag/air resistance/friction?

Answer 15

slows the object down

Question 16

what is lift due to?

Answer 16

an aeroplane wing

Question 17

where is tension?

Answer 17

rope or cable

Question 18

what does any object with a weight feel back form the surface its on?

Answer 18

reaction force

Question 19

what does an object feel in fluid in the opposite direction?

Answer 19

drag

Question 20

why would an object with no force always slow down and stop?

Answer 20

friction

Question 21

to travel at a steady speed what do you always need to counteract friction?

Answer 21

a driving force

Question 22

what 3 ways does friction occur

Answer 22

1.friction between solid surfaces that are gripping
2.friction between solid surfaces which are sliding past each other
3. resistance or drag from fluids

Question 23

how can I reduce friction between two solid surfaces sliding past each other?

Answer 23

putting a lubricant like oil or grease

Question 24

how can I reduce the drag in fluids?

Answer 24

make the object streamlined

Question 25

what do lorries and caravans have to make them more stream line?

Answer 25

deflectors

Question 26

what do roof boxes do to cars speed?

Answer 26

reduce speed as its a less streamline shape and more drag occurs

Question 27

in a fluid what is the relationship between friction increase and speed increase?

Answer 27

friction increases as speed increases

Question 28

what does balanced forces mean?

Answer 28

no change in velocity

Question 29

to keep things moving at a steady speed, what must there be?

Answer 29

zero resultant force

Question 30

when a train/bus/car is moving at a constant speed the forces on it must be ..?

Answer 30

balanced

Question 31

a resultant force means..??

Answer 31

acceleration

Question 32

what happens if there is an unbalanced force?

Answer 32

the object will accelerate in that direction

Question 33

the overall unbalanced force is often called the...?

Answer 33

resultant force

Question 34

the bigger the force the greater the....

Answer 34

acceleration/deceleration

Question 35

the bigger the mass the ....... the acceleration

Answer 35

smaller

Question 36

if object A exerts a force on object B then what does object B exert

Answer 36

an equal ad opposite force on object A

Question 37

A) if you push a shopping trolley hard what will it do? B) if you stop pushing what will the trolley do back

Answer 37

A)push back just as hard B)also stop pushing

Question 38

what is the difference between vector and scalar?

Answer 38

vectors have size and direction whereas scalar only have size

Question 39

what quantity is momentum?

Answer 39

vector

Question 40

what quantity is temperature?

Answer 40

scalar

Question 41

what quantity is time?

Answer 41

scalar

Question 42

what quantity is force

Answer 42

vector

Question 43

what quantity is length?

Answer 43

scalar

Question 44

what quantity is velocity?

Answer 44

vector

Question 45

what quantity is acceleration

Answer 45

vector

Question 46

what quantity is mass

Answer 46

scalar

Question 47

what the resultant force of a 220N force north, a 180N force south and a 90N force south?

Answer 47

220-180-90=-50 so 50N south

Question 48

what is terminal velocity?

Answer 48

when acceleration and resistance force are equal

Question 49

why does the terminal velocity of an object depend on?

Answer 49

their shape and area

Question 50

what is the accelerating force on falling objects?

Answer 50

gravity

Question 51

what is the terminal velocity of an object determined by?

Answer 51

its drag compared to its weight

Question 52

what does drag depend on?

Answer 52

shape and area

Question 53

what does Hooke's law say?

Answer 53

extension is proportional to force

Question 54

a metal spring will also obey Hooke's law is a pair of ........ forces are applied to each end

Answer 54

opposite

Question 55

when does Hooke's law stop working?

Answer 55

when the force is great enough

Question 56

how does a graph show when Hooke's law stops working?

Answer 56

when it curves

Question 57

what is the elastic limit of an object?

Answer 57

-the maximum amount of force you can apply to an object before the material will permanently become stretched

Question 58

what can a material no longer do after being pushed past its elastic limit?

Answer 58

can no longer return to the length at the start, permanently longer

Question 59

what does a material display if it returns to its original shape after elastic deformation (forces have been removed)?

Answer 59

elastic behaviour

Question 60

metals display elastic behaviour as long as....

Answer 60

Hooke's law has been obeyed

Question 61

stopping distance=

Answer 61

thinking distance + braking distance

Question 62

what is the stopping distance of a car?

Answer 62

the distance covered in the time between the driver first spotting a hazard and the car coming to a complete stop

Question 63

what is the thinking distance?

Answer 63

the distance the car travels in the time between the driver noticing the hazard and applying the breaks

Question 64

what is thinking distance affected by? (2)

Answer 64

-how fast your going -your reaction time

Question 65

what is reaction time affected by?

Answer 65

tiredness, drugs, old age, alcohol and inexperience

Question 66

what is breaking distance?

Answer 66

the distance the car travels during its deceleration whilst the breaks are being applied

Question 67

what is breaking distance effected by? (4)

Answer 67

-how fast your going -the mass of the vehicle -how good your brakes are (worn/new) -how good grip is (icy roads, worn tyres)

Question 68

momentum before =

Answer 68

momentum after

Question 69

the greater mass the object has the greater its velocity therefore...

Answer 69

the more momentum it has

Question 70

when is momentum conserved?

Answer 70

when no external forces act

Question 71

what causes change in momentum?

Answer 71

forces

Question 72

what does a larger force mean for momentum?

Answer 72

faster change in momentum (so greater acceleration)

Question 73

if someones momentum changed very quickly (e.g. in a car crash) what forces will be on the body? relate to injury

Answer 73

the forces on the body will be very large and more likely to cause injury

Question 74

what do crumple zones do in a car crash?

Answer 74

crumple on impact, increasing the time taken for the car to stop so change in momentum will be slower and less force will be felt

Question 75

what do seat belts do in a car crash?

Answer 75

stretch slightly, increasing the time taken for the wearer to stop. this reduces the force acting on the chest

Question 76

what do air bags do in a car crash?

Answer 76

slow you down more gradually to reduce the time taken for momentum change therefore less force on the passenger

Question 77

what is moment?

Answer 77

the turning effect of a force

Question 78

A)what does a force on a spanner cause on the nut? B) if a greater force is applied what happens to the nut

Answer 78

A) a turning effect (moment) B) bigger moment, turns more

Question 79

what happens to the moment if a larger spanner is used with the same force? and why?

Answer 79

a larger moment because the distance from the pivot is greater

Question 80

at what angle must I push to get the maximum moment?

Answer 80

right angle

Question 81

why would pushing at a non right angle mean a smaller moment?

Answer 81

because the perpendicular distance between the line of action and the pivot is smaller

Question 82

what is the centre of gravity of an object?

Answer 82

the point through which the weight of a body acts

Question 83

when does a freely suspend object swing until?

Answer 83

until its centre of gravity is vertically below the point of suspension

Question 84

what does it create when the weight acts at a distance from the pivot?

Answer 84

a moment

Question 85

how can I find the centre of gravity in any flat shape? (4)

Answer 85

1.suspend the shape and a plumb line from the sam point and wait until they stop moving 2.draw a line along the plumb line 3.do the same thing again, but suspend the shape from a different pivot point 4.the centre of gravity is where the two lines cross

Question 86

what doe the principle of moment say?

Answer 86

if an object is balanced then total anticlockwise moment = total clockwise moment

Question 87

if a light rod is being supported at both ends, will the upwards force provided always be the same by each support?

Answer 87

no, will not always be the same

Question 88

if a heavy object is placed on a rod which support will provide a larger force?

Answer 88

the support closest to the object

Question 89

what happens if the moments are not equal?

Answer 89

if the total anticlockwise moment do not equal the total clockwise moment then there will be a resultant moment

Question 90

what happens is there is a resultant moment?

Answer 90

the object will turn