P10 Forces and Motion (paper 2)

Question 1

what is the equation for acceleration

Answer 1

a = Force / mass

Question 2

what is newtons 2nd law

Answer 2

If a resultant force is applied to an object it will accelerate

Question 3

define inertia

Answer 3

resistance in change of motion

Question 4

define inertial mass

Answer 4

a measure of how difficult it is to change the velocity of an object

Question 5

what is Newton’s 1st law

Answer 5

Objects remain at rest or in uniform motion unless an external force acts

Question 6

what is Newton’s third law

Answer 6

Every object has an equal and opposite force

Question 7

how do you calculate the weight of an object knowing their mass

Answer 7

weight = mas x gravitational field strength

Question 8

what is the gravitational field strength on earth

Answer 8

9.8

Question 9

what is a moment

Answer 9

the turning force of an object

Question 10

how do you calculate the moment of an object

Answer 10

moment = force x distance

Question 11

what do levers do

Answer 11

make it easier for us to do work

Question 12

what do gears do

Answer 12

transmit rotational effects

Question 13

how do gears work

Answer 13

different sized gears are used to change the moment of forces

Question 14

what do objects in fluids eperience

Answer 14

upthrust
weight = upthrust

Question 15

what does the stopping distance equal

Answer 15

stopping distance = thinking distance + braking distance

Question 16

what is the thinking distance

Answer 16

how far a object travels during the drivers reaction time

Question 17

what is the braking distance

Answer 17

the distance taken to stop under the breaking force

Question 18

what affects the thinking distance

Answer 18

• speed = faster = further before reaction
• reaction time = longer = longer before break applied

Question 19

what factors affect the braking distance

Answer 19

• speed = longer to stop
• weather/surface = friction
• tyre condition
• brake quality = worn/faulty

Question 20

what is the braking distance for a car at 30mph

Answer 20

14m

Question 21

what is the braking distance for a car at 60mph

Answer 21

55m

Question 22

what is the braking distance for a car at 70mph

Answer 22

70m

Question 23

how do you calculate the momentum of an object

Answer 23

p = mass x velocity

Question 24

what is the conservation of momentum

Answer 24

the total momentum before an event = the total momentum after an event

Question 25

how do you calculate change in momentum

Answer 25

mass x ((origanl - current) / time)

Question 26

what is the difference between a vector and scalar quantity

Answer 26

vector involves magnitude and direction, scalar is just magnitude

Question 27

what are the units used for a moment

Answer 27

Nm

Question 28

what is the resultant force

Answer 28

the overall force acting on an object when multiple forces are acting on it

Question 29

how do we represent force

Answer 29

in a scale diagram

Question 30

what is the resolving force

Answer 30

finding the horizontal and verticle components of a single force

Question 31

what is hookes law

Answer 31

the extension of an elastic object is directly proportional to the force applied, provided that the limit of proportionality is not exceeded

Question 32

what is the equation for hookes law

Answer 32

force = spring contasnt x extension

Question 33

define elastic deformation

Answer 33

when the forces are removed the object returns to its original length

Question 34

if an object is balanced describe the clockwise and anitclockwise froces

Answer 34

they must be equal

Question 35

what is the equation for pressure

Answer 35

p = force / area

Question 36

what is terminal velocity and when does it occur

Answer 36

the maximum velocity an object can fall at, this happened when forces are balanced

Question 37

Define centre of mass

Answer 37

The centre of mass is the point at which the object will balance

Question 38

what is the limit of proportionality

Answer 38

the point beyond which Hooke's law is no longer true when stretching a material. It is the point where the object no longer deforms elastically and starts to deform inelastically

Question 39

what is the typical reaction time for a human

Answer 39

0.2 - 0.9 seconds