Paper 2 speed velocity and energy Flashcards

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1
Q

Scalars

A

Quantities that are fully described by a magnitude or size (or numerical value) alone

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2
Q

Vectors

A

Quantities that are full described by both a magnitude and a direction

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3
Q

On a distance time graph what does a diagonal line mean

A

It means it’s moving at a constant speed

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4
Q

On a distance time graph what does a horizontal line mean

A

It means the object has stopped

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5
Q

On a distance time graph what does a steeper diagonal line mean

A

It means the object is going faster but still at a constant speed

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6
Q

On a distance time graph what does a diagonal line downwards mean

A

It means the object is going back to the start/ reversing still at a constant speed

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7
Q

What is speed

A

How fast you are travelling and is scalar

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8
Q

What is velocity

A

Speed in a given direction and is vector

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9
Q

Acceleration (m/s^2) =

A

Change in velocity (m/s)/ time taken (s)

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10
Q

In a velocity time graph what does an upwards line mean

A

It means the object is accelerating constantly

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11
Q

In a velocity time graph what does horizontal line mean

A

It means the car has stopped accelerating and is moving at a constant velocity

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12
Q

In a velocity time graph what does a shallower line mean

A

It means the object is accelerating less but still constant

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13
Q

In a velocity time graph what does a downwards line mean

A

It means the object is slowing down/ decelerating

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14
Q

In a velocity time graph what does the area under the graph mean

A

It shows the distance travelled D=ST

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15
Q

What is gravity

A

Gravity is a field not a force. The force due to gravity on an object is its weight

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16
Q

What force is acting on a book at rest and what is the equal and opposite force?

A

Friction is acting on the book and the equal and opposite force is the reaction of the table.

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17
Q

What force is acting on a floating ball and what is the equal and opposite force?

A

The force acting is the upthrust of water and the equal and opposite force is the weight of balls

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18
Q

What is the resultant force

A

A single force that has the same effect as all the forces combined

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19
Q

What happens if the forces on an object are unbalanced?

A

The object will accelerate

20
Q

What is the thinking distance

A

The distance the car travels during reaction time

21
Q

Thinking distance increases if…

A

Distractions
Tired
Under influence of alcohol or drugs
Driving fast

22
Q

What is the braking distance

A

The distance car travels while the brakes are applied

23
Q

Braking distance increase if…

A
High mass of car
Wet/icy road
Gravel on road
Worn down tires
Faulty brakes
24
Q

What is the stopping distance

A

Thinking distance + braking distance

25
Q

Thinking distance is proportional the speed so…

A

If the speed doubles the thinking distance doubles

26
Q

Braking distance is proportional to speed squared so…

A

If the speed is doubles, the braking distance is quadrupled

27
Q

What is Newton’s first law of motion

A

An object will remain at rest or will move at a constant velocity unless there is a resultant force acting on it

28
Q

What is Newton’s second law of motion

A

The acceleration of an object is directly proportional to the resultant force and inversely proportional to the object mass

29
Q

What is Newton’s third law of motion

A

If object A exerts a force on object B the object B exerts a force on object A which is equal and opposite in size and direction

30
Q

What do you do if the force of the two vectors are in the same direction

A

The add together

31
Q

What do you do if the two vectors are at 90 degrees

A

Use Pythagoras theorem

32
Q

When is it best to use the head to tail method

A

When the vectors are displacements because they have an obvious order

33
Q

When do we use parallelogram of forces

A

When there are forces

34
Q

What is the weight of an object

A

The force of gravity acting on it

35
Q

What is the mass of an object

A

The amount of matter in it

36
Q

What happens if an object falls freely

A

No other forces act on it so the resultant force is its own weight. Accelerates downwards at constant acceleration of 10m/s^2 called the acceleration due to gravity

37
Q

What if the object falls in a fluid

A

The fluid drags on an object and the drag force increases with speed. The resultant force on the object is its weight minus the drag force.

38
Q

Work done

A

When any object is moved around work will need to be done on it to get it to move

39
Q

What energy does elastic store

A

Elastic potential energy is stored in elastic when work is done on a an object

40
Q

What happens to ‘plastic’ objects when the forces deforming it are removed

A

The objects don’t regain its original shape

41
Q

Hookes law

A

States that the extension of a spring is in direct proportion with the force applied to it e.g. If the force is doubled the extension is doubled (F=ke)

42
Q

What does hookes law apply to

A

Only elastic materials

43
Q

What happens if the force added on the spring is larger

A

It stops being elastic and doesn’t return to its original length. It has exceeded the limit of proportionality and so Hookes law no longer applies. This is known as elastic limit

44
Q

What is inertial mass

A

A measure of how difficult it is to change the velocity of an object. defined by the ration of force over acceleration

45
Q

What happens to the acceleration of an object falling in water

A

Acceleration decreases as it falls because drag force increases as the object speeds up so the resultant force on it decreases