Brainscape's Knowledge GenomeTM

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


See full index

Physics > SP2- Motion And Forces > Flashcards

SP2- Motion And Forces Flashcards

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

What is the difference between a vector quantity and a scalar quantity

A

vector quantities has direction and magnitude

Scalar quantities only have magnitude

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

What’s acceleration

A

Is a change in a vector quantity (velocity) acceleration is also a vector

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

What type of quantity is a force

A

A vector

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

How is the size of the force represented in a diagram

A

The length of the arrows

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

What is the resultant force

A

The overall force of an object

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

How do yu work out the resultant of 2 forces

A

If the forces are acting in the same direction add them

If they are acting in opposite directions subtract them

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

What happens if the resultant forces of an object is 0

A

The forces are balanced

If there is a non zero resultant force on an object the forces are unbalanced

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

What’s Newton’s first law of motion

A

A moving object will continue to move at the same speed and direction unless an external force
Acts on it

A stationary object will remain at rest unless an external force acts on it

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

How could forces change the speed and/or direction of an object

A

If there are balanced forces it will not change

If there are unbalanced forced the speed and/ or direction of an object will change

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

What’s the centripetal force

A

The resultant force that causes the change in direction

Eg an object moving in a circle has changing velocity even though it’s speed remains the same

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

Tell me about the centripetal force

A

Acts towards the centre of a circle

Other types of force that can make objects move in circular paths include friction and gravity

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

What is mass

A

The quantity of matter there is in an object

It only changes if the object itself changes

Units are kilograms

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

What is weight

A

A measure of pull of gravity of an object and depends on the strength of gravity

Units are newtons

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

How can weight be measured

A

Using a force meter which has a scale in newtons

Many contain a spring which stretches as the force on it increases allowing her weight to be read of the scale

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

What’s the earths gravitational field strength

A

10 N/kg

Every kg is pulled down with a force of 10 newtons

The field strength is different on other planets and moons

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

Tell me the triangle that links weight, mass and gravitational field strength

A

W on the top (weight) and m(mass) X gravitational field strength on bottom

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

How does air resistance increase

A

With speed

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

What is newtons Second law of motion

A

The acceleration in the direction of a resultant force depends on

The size of the force (for same mass, bigger force bigger acceleration)

The mass of an object (for the same force, the more massive the object the smaller the acceleration)

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

How do you calculate force

A

Force (n) = mass (kg) X acceleration (m/s^2)

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

What’s the inertial mass

A

The inertial mass of an object is the force on it divided by the acceleration that force produces

The more massive an object is - the more force is need to change its velocity.

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

Tell me about Newton’s third law

A

It’s about the forces on two different objects when they interact with eachother

This interaction can happen;

When objects touch- such as when you sit on a chair

At a distance, such as the gravitational attraction between the earth and the moon

22
Q

What are action-reaction forces

A

There is a pair of forces acting on the two interactive objects

The two forces are Always the same size and in opposite directions, they are also the same type of force

23
Q

What’s a equilibrium situation

A

When nothing is moving eg when a there is a tug of war

24
Q

How are action-reaction forces different to balanced forces

A

In both cases the sizes of the forces are equal and act in opposite direction but:

Action-reaction forces act on different objects

Balanced forces all act on the same object

25
Q

Tell me about collisions

A

The action and reaction forces that occur during the collision are the same size but don’t necessarily have the same effects on the 2 objects Becuase the objects have different masses

26
Q

What is momentum

A

A measure of the tendency of an object to keep moving or of how hard it is to stop it moving

The momentum of an object depends on its mass and its velocity

Momentum depends on a vector quantity (velocity) and Momentum is also a vector

27
Q

How is momentum calculated

A

P (momentum) (kg m/s) on top of triangle and m (mass) (kg) X v (velocity) (m/s) on bottom

28
Q

Tell me the 3 ways to work out force

A

F = m(v-u) divided by t

Or f = mv - mu divided by t

Or f = m X a

29
Q

How do you work out change in velocity and time

A

A = v-u divided by t

30
Q

What’s the conservation of momentum

A

When moving objects collide the total momentum of both objects is the same before the collision as it is after the collision - as long as there are no external forces acting

31
Q

How do we show momentum

A

If the objects are moving in opposite directions we give the momentum of one object a positive sign and the other a negative

32
Q

What’s the thinking distance

A

When a driver sees a problem ahead - their vehicle will travel some distance while the driver reacts to the situation

33
Q

What’s the braking distance

A

The vehicle will then go some distance further while the brakes are working to bring it to a halt

34
Q

What is the stopping distance

A

The sum of the thinking and braking distances

Stopping distance = thinking distance + braking distance

35
Q

What is the reaction time

A

The time between a person detecting a stimulus and their response

36
Q

How can response times be measured

A

Using computers or electric circuits that measure the time between a stimulus and a response

37
Q

What’s a typical reaction time to a visual stimulus

A

0.25 seconds

38
Q

Why could a reaction time be longer

A

If the person is tired, Ill, or been taking drugs as alcohol

Distractions such as mobile phones can also increase reaction times

39
Q

How do cars break

A

Uses friction so slow car down

40
Q

How can the braking distance be increased

A

If the brakes are worn - they create less friction and don’t slow the vehicle effectively

Friction between the tyres and road is also important
If the road is wet or has loose gravel on it - or if the tyres are worn there is less friction

41
Q

A heavier vehicle needs what to decelerate

A

More force - so if the same amount of friction is used to syllable a vehicle the heavier vehicle will travel further than a lighter one

42
Q

When does think distance and braking distance increase

A

As the speed increases

43
Q

What is the work done

A

The energy transferred by a force acting over a distance

44
Q

How do you calculate work done

A

Work done (J) = force (N) X distance moved in the direction of the force (m)

45
Q

What is kinetic energy

A

The Energy stored in a moving object

46
Q

How do we calculate kinetic energy

A

Kinetic energy (J) = 1/2 X mass (kg) X speed^2 (m/s^2)

47
Q

What happens to kinetic energy when it stops

A

The kinetic energy is transferred to other energy strokes by the braking force

48
Q

Tell me the work done, force and distance triangle

A

Work done on top and force X distance on bottom

49
Q

The braking distance of a car depends on its kinetic energy and so…

A

It depends on the square of its velocity

So if the velocity doubles - the braking distance is multiplied by 2^2 which is 4

50
Q

What does the force need for acceleration depend on

A

Th size of acceleration and on the mass of the object

51
Q

What are crumple zones

A

Built into the front and sometimes the back of cars - if the car hits something it takes a little time for this crumpling to happen

So the deceleration of the car is less and the force on the car is also less than if it had a solid front

The effect of the crumple zone reduces the forces in the passengers as well as on the car

Airbags increase the time it takes a persons head to stop a collision

52
Q

What does the force in a road collision depend on

A

The change of momentum as the car comes to a stop

Physics (13 decks)

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