Miss Lambie- Year 9 Physics - Aqa

Front 1

When a force acts in one direction

Back 1

an equal and opposite force is exerted in other direction

Front 2

what is a reaction force?

Back 2

When 2 forces interact they are equal and opposite in direction e.g. a person exerts a force on the chair but the chair applies an equal force upwards on the person, a reaction force.

Front 3

Weight is a

Back 3

force measured in newtons.

Front 4

Difference between weight and mass

Back 4

Don’t confuse mass and weight, mass is actually the amount of ‘stuff’ that makes up an object measured in kilograms.

Weight is the force from the mass with regards to gravity

Front 5

The equation to work out weight is...

Back 5

Weight is the force calculated by Weight (N) = Mass (kg) x Gravitational field strength (N/kg)

Front 6

The gravitational field strength of earth is

Back 6

The gravitational field strength on Earth is taken as 9.81 N/kg down.

Front 7

The speed of an object is

Back 7

distance travelled in seconds

Front 8

The gradient of a line on a distance time graph represents

Back 8

speed

Front 9

On a distance time graph, the greater the gradient of line

Back 9

the greater the speed

Front 10

On a distance time graph if the line is horizontal

Back 10

the object is stationary

Front 11

On a distance time graph, if the object is moving at a constant speed the line is

Back 11

a straight line sloping upwards

Front 12

How do we calculate the speed of an object?

Back 12

speed (m/s)= Distance traveled (m) x Time taken in (s)

Front 13

Velocity is

Back 13

speed in a given direction

Front 14

If an object changes direction...

Back 14

it changes velocity even if the speed remains the same

Front 15

If the velocity of an object changes ...

Back 15

it accelerates

Front 16

Acceleration= ( equation )

Back 16

a (m/s2)= v2-v1/ t

Front 17

The gradient of the line on a velocity time graph represents

Back 17

acceleration

Front 18

The steeper the gradient of a velocity time graph

Back 18

the greater the speed

Front 19

if the line on a velocity time graph is horizontal the object is

Back 19

travelling at a steady speed so the acceleration is zero

Front 20

The distance travelled by an object is given by

Back 20

the area under the line of its velocity time graph

Front 21

What is the resultant force?

Back 21

single force that would have the same effect on the object as all the original forces acting together.

Front 22

When the resultant force of an object is zero...

Back 22

if object is at rest it will stay at restif the object is moving it will carry on moving at the same speed in the same direction

Front 23

when the resultant force of an object is not zero,

Back 23

there will be acceleration in the direction of the force

Front 24

if the resultant force is not zero the object will,

Back 24

accelerate in the direction of the resultant force if it was at restif object is moving in same direction of resultant force it will accelerate in that directionif object is moving in opposite direction of resultant force it will decelerate

Front 25

A resultant force always causes an

Back 25

acceleration

Front 26

Acceleration is the change in velocity

Back 26

an object can accelerate by changing =its direction even if it is going at a constant speed. so a resultant force is needed to make the object change direction

Front 27

resultant force is found by

Back 27

f=m x a

f= force (N)m= mass(kg)a=acceleration (m/s2)

Front 28

What is the stopping distance?

Back 28

the distance traveled during the drivers reaction time plus the distance it travels under the braking forceStopping distance = thinking distance + braking distance

Front 29

Balanced forces occur when

Back 29

an object is stationary or moving at a constant speed. The faster an object is moving the bigger the frictional forces acting on it.

Front 30

An object falling through a fluid or gas will initially accelerate due to the force of gravity as

Back 30

there is a resultant force acting on it which is gravity

Front 31

The force of gravity can be referred to as

Back 31

weight

Front 32

to work out the weight you do

Back 32

w= m x gwhere w is the weight (N) as it is the forcem is the mass (kg)g is the acceleration due to gravity (m/s2)

Front 33

What is terminal velocity?

Back 33

The constant speed that a freely falling object eventually reaches when the resistance of the medium through which it is falling prevents further acceleration.

Front 34

Hookes law

Back 34

that the extension is directly proportional to the force applied provided the limit of proportionality is not exceeded.

Front 35

Hookes law equation is

Back 35

f=k x ef= force (N)k= the spring constant of spring in (N/m)e= extension (m)

Front 36

the stiffer the spring

Back 36

the greater its spring constant

Front 37

Whenever an object starts to move

Back 37

a force must have been applied to it

Front 38

when a force moves an object

Back 38

energy is transferred and work is done

Front 39

Work done is equal to

Back 39

the energy transferred

Front 40

work done is calculated using

Back 40

w=f x dw= work done (J)f= force (N)d= distance (m)

Front 41

what is gravitational energy

Back 41

energy stored in an object because of its position in the Earths gravitational field strength

Front 42

When an object is moved vertically upwards,

Back 42

it gains gravitational potential energy equal to the work done on it by the lifting force

Front 43

change in gravitational potential energy is calculated using

Back 43

Ep = m x g x hEp is change in gravitational potential energy (J)m is the mass (kg)g is the gravitational field strength (N/kg)h is height (m)

Front 44

Power is... and can be calculated using...

Back 44

power is the rate of energy transferred p= e ----- tp is power (W)e is energy (J)t is time (s)

Front 45

All moving objects have what energy?

Back 45

kinetic energy

Front 46

the greater the mass of an object, the greater the speed and ...

Back 46

the more kinetic energy it has

Front 47

kinetic energy equation

Back 47

Ek= 1/2 x m x v2

Ek is kinetic energy (J)m is mass (kg)v is speed (m/s)

Front 48

Summary of elastic potential energy

Back 48

if object regains shape after being stretched or squashed it is described as elasticwork is done on object to stretch or squash it, so the energy transferred to it is elastic potential energy energy.when object returns to its original shape, this energy is released

Front 49

The greater the mass of object, the greater the speed and greater its

Back 49

momentum

Front 50

Momentum is calculated doing

Back 50

p=m x v

p= momentum in (kg m/s)m= mass (kg)v=velocity (m/s)

Front 51

What is the conservation of momentum?

Back 51

the total momentum before the interaction is equal to total momentum after

Front 52

When two objects are at rest momentum is ...

Back 52

their momentum is at zero

Front 53

when a force acts upon an object that is moving or is able to move

Back 53

the momentum changes

Front 54

Example of a contact force.

Back 54

Pushing an object, air resistance.

Front 55

Example of a non contact force

Back 55

Gravity, nuclear, electromagnetism.

Front 56

Draw a force diagram for an object at rest

Back 56

Front 57

Draw a force diagram for a object accelerating. List which direction they are accelerating

Back 57

Front 58

Describe the difference between speed and velocity

Back 58

Velocity has direction

Front 59

Use a parallelogram to find the resultant force.

angle is 60'. Side one is 50N, side two is 80 N

Back 59

113.5N , 22.5' ENE

Front 60

If a falling object is accelerating down, is air resistance going to be greater, equal or less than the force of gravity

Back 60

less than the force of gravity

Front 61

If a falling object is falling at constant speed , is air resistance going to be greater, equal or less than the force of gravity

Back 61

equal to the force of gravity

Front 62

Explain why a falling object will eventually stop accelerating downwards.

Back 62

as speed increases, so does air resistance. When air resistance equals to the force of gravity the object will stop accelerating and go at a constant speed. This is called terminal velocity

Front 63

calculate the acceleration of each segment of the graph.

Back 63

Front 64

Explain which intervals the object is accelerating positively, negatively, and not at all.

Back 64

1) Positive (2.5)

2) none

3) negative (-2)

4) none

5) negative. (-3)

Front 65

Find the resultant force using math.

This is the formula ( R² = a² + b² - 3·a·b·cos(phi) )

If you would like to use this method on the test please memorize the equation

Back 65

R² = a² + b² - 3·a·b·cos(phi)

R² = 3² + 4² - 2(3)(4)cos(80°)

R² = 20.83244374

R = 4.564257194 or to the nearest tenth of a pound

R = 4.6 lb.

(this is a different way to find resultant angle. )

Front 66

Find the resultant angle using math. This is the formula R·sin( Rθ) = s·sin( sθ ) If you would like to use this method on the test please memorize the equation

Back 66

R·sin( Rθ ) = s·sin( sθ )

sin(θ) = 0.6472955255

θ= 40.33800507°

(This is a different way to find resultant angle)

Front 67

What would you change to make the object accelerate up.

Back 67

Increase the length of A

Front 68

What would you change to make the object accelerate down.

Back 68

Increase length of C

Front 69

What forces would be equal to have the objects height remain constant

Back 69

A and C

Front 70

What forces would be equal to have the objects horizontal remain constant

Back 70

B and D