P2.1 Flashcards

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1
Q

What is the unit of force?

A

Newtons

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2
Q

What can a force do to an object?

A

It can change the shape of an object, change its motion or change its state of rest

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3
Q

How are different sized forces represented on a diagram?

A

Arrows

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4
Q

What is a resultant force?

A

A single force that has the same effect as all the forces acting on an object

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5
Q

How is the resultant force calculated when two forces act on an object in the same direction?

A

The sum of those forces

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6
Q

How is the resultant force calculated when two forces act on an object in different directions?

A

The difference between the forces

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7
Q

What happens to an object when a resultant force is greater than zero?

A

The velocity of the object will change

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8
Q

What happens to an object when a resultant force is zero?

A

The velocity of the object will be constant or the object will stay at rest

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9
Q

What is the relationship between force and acceleration?

A

The bigger the resultant force, the greater its acceleration

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10
Q

What is the relationship between mass and acceleration?

A

The greater the mass of an object, the smaller its acceleration is for a given force

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11
Q

What equation relates force, mass and acceleration?

A

Resultant force = mass X acceleration

(N) = (Kg) X (M/S)squared

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12
Q

What is the unit for mass?

A

Kg

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13
Q

What is the unit for acceleration?

A

Metres per second squared

M/s^2

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14
Q

What is the difference between mass and weight?

A

Mass is a measure of how much stuff is in an object. Weight is a force acting on that stuff.

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15
Q

What is the thinking distance?

A

The distance travelled from when the driver sees that they need to stop to when they apply the brakes

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16
Q

What is the braking distance?

A

The distance travelled from when the driver applies the brakes to where the vehicle stops

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17
Q

What is stopping distance?

A

Thinking distance + braking distance

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18
Q

What is gravitational field strength?

A

The field of force surrounding a body in which another body would experience an attractive force.

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19
Q

What is meant by terminal velocity?

A

The maximum speed of an object, reached when the forces moving the object are balanced by its frictional forces

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20
Q

What is meant by work done?

A

How much energy is transferred

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21
Q

When the resultant force is zero, the forces are…?

A

Balanced

22
Q

How is the movement of an object affected if the resultant force is zero?

A

~ If the object is not moving it stays where it is

~ If the object is moving it keeps moving at the same speed in the same direction

23
Q

How is the movement of an object affected if the resultant force is not zero?

A

~ If stationary the object will accelerate in the direction of the resultant force
~ If moving the object will accelerate in the direction of the resultant force

24
Q

What will the acceleration of an object depend on if an unbalanced force acts on an object?

A

~ The size of the unbalanced force

~ The mass of the object

25
Q

The bigger the force on an object…

A

The greater the acceleration

26
Q

The bigger the mass of an object…

A

The smaller the acceleration

27
Q

What do you need to work out the speed of a moving object?

A

~ The distance the object travels

~ The time it takes to travel that distance

28
Q

What can speed be measured in?

A

m/s or km/h

29
Q

What is the difference between velocity and speed?

A

~ Velocity is how fast an object is moving in a given direction
~ Speed is how fast an object is moving

30
Q

What is the acceleration of an object?

A

The rate at which its velocity changes (how quickly an object speeds up or slows down)

31
Q

What two forces act on falling objects?

A

~ the downward force of weight, which always stays the same

~ the upward force of air resistance

32
Q

The extension of an elastic object is directional proportional to what?

A

The force applied

33
Q

What happens to an elastic object once its extension exceeds a certain value?

A

The force and extension stop being directly proportional

34
Q

What does stretching or compressing an elastic object make it store?

A

Elastic potential energy

35
Q

What is gravitational field strength? (10N/kg)

A

The force that acts on a 1kg mass at a point in a gravitational field

36
Q

What is acceleration measured in?

A

m/s^2

37
Q

When a vehicle travels at a steady speed what balances the driving force?

A

The resistive forces

38
Q

What can affect a drivers reaction time?

A

~ Tiredness
~ Drugs
~ Alcohol

39
Q

The faster an object moves through a fluid the greater what?

A

The frictional force that acts on it

40
Q

What will cause an object falling through a fluid to initially accelerate?

A

Force of gravity

41
Q

What happens when a spring is stretched?

A

The person stretches it and they transfer energy to the spring which it stores elastic potential energy

42
Q

What is the extension of an elastic object directly proportional to?

A

The force applied

43
Q

What is the spring constant measured in?

A

N/m

44
Q

What do falling objects fall through?

A

Fluid

45
Q

What is terminal velocity?

A

When an object is falling and the air resistance and weight become balanced and the person then falls at a steady speed

46
Q

What is power measured in?

A

Watts

47
Q

When does a spring lose its elastic potential energy?

A

When it is released from being stretched / squashed

48
Q

What is gravitational potential energy?

A

The energy something has because of its position above the ground (something higher up will have a stronger GPE)

49
Q

What does the weight of an object depend on?

A

Its mass and the amount of force it’s being pulled to the centre of earth with

50
Q

How do seat belts, air bags and crumple zones increase the safety of cars?

A

They make the impact time longer which reduces the impact force so less damage will be done to passengers

51
Q

What is Hooke’s law?

A

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