Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Physics⚡️ > Chapter 10 > Flashcards

Chapter 10 Flashcards

You may prefer our related Brainscape-certified flashcards:
Physics 101 flashcards AP® Physics flashcards
1
Q

Equation for resultant force

A

Resultant force = mass x acceleration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What does Netwon’s second law say? 2

A

The acceleration of an object is:
Proportional to the resultant force on the object
Inversely proportional to the mass of the object

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What do we need to change the velocity of an object?

A

Resultant force

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is inertia?

A

The tendency to continue in the same state of motion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the inertial mass of an object?

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Equation for inertial mass

A

Force / acceleration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the acceleration of an object the sane as?

A

The resultant force

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

When does the object decelerate?

A

When the resultant force is in the opposite direction to the velocity of the object

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

When does an object accelerate?

A

When the resultant force is in the same direction as the velocity of the object

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Why does an object fall?

A

Its weight

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is your weight caused by?

A

The forec of attraction between you and the earth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Why do you weigh less at the equator?

A

Weaker force of attraction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How much is 1 N?

A

100 g

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is your weight? (N)

A

The force acting on you due to gravity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is your mass? (kg)

A

The quantity of matter inside you

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Equation for weight (kg)

A

weight = mass x gravitational field strength

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

In which direction will friction always act?

A

Opposite to the direction of movement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

When an object falls in a fluid, why does its acceleration decrease as it falls?

A

The frictional force increases as it speeds up, so the resultant force on it decreases and therefore its acceleration decreases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

When does an object reach terminal velocity?

A

When the frictional force on it is equal and opposite to its weight and accelerating force

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How does streamlining help?

A

Reduces drag so the fluid flows easily around the object

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What happens when an object reaches terminal velocity?

A

It falls at a constant speed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What causes objects to fall at different speeds on earth?

A

Air resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What does the frictional force of an object depend on?

A

Its shape and area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What does the braking distance of a vehicle depend on?

A

Its mass and speed when the brakes are applied

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Why is it harder to stop when you are going faster?

A

The greater the deceleration needed, so the braking force needed is much greater

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is a stopping distance?

A

The shortest distance a vehicle can safely stop in

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

How to work out stopping distance?

A

Thinking distance + braking distance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is the thinking distance?

A

The distance travelled by the vehicle in the time it takes the driver to react

29
Q

What is thinking distance equal to?

A

Speed x reaction time

30
Q

Why is thinking distance proportional to speed?

A

The car travels at a constant speed during the time it takes the driver to react

31
Q

What is the braking distance?

A

The distance travelled during the time the braking force acts

32
Q

Equation for stopping distance?

A

Thinking distance + braking distance

33
Q

What two things is thinking distance affected by?

A

Speed and reaction time

34
Q

Why does speed increase thinking distance?

A

The faster you’re travelling, the further you’ll travel in the time it takes you to react

35
Q

Examples of things increasing thinking distance? 4

A

Tiredness, alcohol, distractions and drugs

36
Q

4 things affecting braking distance

A

Speed, weather, condition of tyres, condition of brakes

37
Q

What does the deceleration of a vehicle depend on?

A

The friction between the road surface and the tyres

38
Q

Why does the condition of the road affect braking distance?

A

If it is wet or icy, there is less friction between the tyres and road, increasing your braking distance

39
Q

Why does the condition of the tyres affect braking distance?

A

If tyres don’t have any tread left, they can’t get rid of water in wet conditions, meaning they skid

40
Q

Why does the condition of brakes affect braking distance?

A

Worn brakes won’t be able to apply as much force

41
Q

Equation for deceleration

A

a = (v^2 - u^2) / 2S

42
Q

What happens when the brake pedal is pressed?

A

The brake pads press onto the wheels
This causes friction, which causes work to be done
The work done transfers energy from the kinetic store of the wheels to the thermal store of the brakes, causing them to heat up

43
Q

Equation for momentum

A

momentum (kg m/s) = mass x velocity

44
Q

Why is momentum a vector?

A

It has size and direction

45
Q

What is the conservation of momentum?

A

In a closed system, the total momentum before an event is equal to the total momentum after an event

46
Q

What happens when things collide?

A

They recoil with equal and opposite momentum

47
Q

When two objects collide and stick together, what happens?

A

Before: The momentum was equal to the mass x velocity of the moving object
After: The weight has increased, so velocity decreases

48
Q

What is important to remember in momentum calculations?

A

One object has positive momentum, the other has negative momentum

49
Q

Equation for the conservation of momentum

A

(mass of A x velocity of A) = -(mass of B x velocity of B)

50
Q

What happens when the impact time is increased?

A

The impact force reduces

51
Q

Equation for force

A

(mass x change in velocity) / time taken
SO
change in momentum / time taken

52
Q

Why does a car crash injure a person?

A

Their change in momentum is very big, so the force exerted on their body will be greater

53
Q

What happens when two cars collide?

A

They exert equal and opposite impact forces on eachother

54
Q

Why do we want to increase impact time?

A

It decreases the force exerted on a person

55
Q

Why should you wear a cycle helmet?

A

It contains a crushable layer of foam which helps lengthen the time for your head to hit the ground and stop moving. This reduces the force of the impact

56
Q

Why do seatbelts keep us safe?

A

1) The seatbelt is across the chest so spreads the force that would otherwise injure the person’s head out
2) They stretch, which increases the time taken for us to stop moving and so decreases the force

57
Q

How do airbags keep us safe?

A

In a crash, they inflate before we hit the dashboard
It spreads the force of the impact across the upper part of a person’s body and increases the impact time
So, the effect of the force is weaker

58
Q

How do playmats keep us safe?

A

They are made of foam so increase the time it takes us to stop moving

59
Q

How do crumple zones keep us safe?

A

They increase the time taken for a car to stop

60
Q

What is braking distance proportional to?

A

Speed squared

61
Q

What is an elastic object?

A

One that can go back to its original shape when the forces that are deforming it are removed

62
Q

What happens when an object is elastically deformed?

A

Work is done when a force stretches or compresses an object and causes energy to be transferred to its elastic potential store
If it is elastically deformed, all this energy is transferred to the elastic potential store

63
Q

How to calculate the extension of a spring?

A

The extended length - the original length

64
Q

What is the extension of a spring directly proportional to?

A

The force applied

65
Q

What happens to the spring constant as the spring gets stiffer?

A

Increases

66
Q

What is Hooke’s law?

A

The extension of a spring is directly proportional to the force applied, as long as the limit of proportionality is not reached

67
Q

Equation for Hooke’s Law?

A

Force applied = spring constant x extension

68
Q

What does the limit of proportionality look like on a graph?

A

The regular gradient will bend or change

69
Q

What happens when a spring reaches its limit of proportionality?

A

It won’t go back to normal

Physics⚡️ (16 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions