Forces Flashcards

1
Q

A value with magnitude only is a ________?

A

scalar

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2
Q

A value with magnitude and direction is a ____________?

A

vector

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3
Q

Distance an speed are examples of _________ quantities

A

scalar

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4
Q

Force, displacement and velocity are examples of __________ quantities

A

vector

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5
Q

What is a contact force?

A

A force between two object which are touching

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6
Q

What ia a non-contact force?

A

A force between objects which are separated by space.

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7
Q

Give two examples of contact forces

A

e.g. friction, air resistance

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8
Q

List three non-contact forces

A

gravitational, electrostatic, magnetic

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9
Q

Define weight

A

The force of gravity acting on an object’s mass

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10
Q

What device is used to measure weight?

A

A newtonmeter

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11
Q

What is the name of the single point at which an object’s mass appears to act?

A

centre of mass

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12
Q

The center of mas of an object is…

A

the single point at which the objects weight appears to act.

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13
Q

The single force which has the same effect as the combination of all the different forces acting on an object is the ______________ _______________.

A

resultant force

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14
Q

Work is done when an object is ….

A

… moved through a distance

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15
Q

Moving objects with mass are said to have __________?

A

momentum

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16
Q

State the law of conservation of momentum

A

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

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17
Q

State the equation which links gravitaional field strength, mass and weight

A

W=mg

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18
Q

State the equation which links distance, force and work done

A

W=Fs

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19
Q

State the equation which links extension, force and spring constant

A

F=ke

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20
Q

State the equation which links distance, speed and time

A

s=vt

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21
Q

State the equation which links acceleration, change in velocity and time taken

A

a=Δv/t

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22
Q

State the equation which links acceleration, mass and resultant force

A

F = ma

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23
Q

State the equation which links mass, momentum and velocity

A

ρ = mv

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24
Q

What is the unit of weight?

A

Newtons (N)

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25
What is the unit of mass?
kilograms (kg)
26
What is unit of gravitational field strength?
newtons per kilogram (N/kg)
27
What is the unit of work done?
Joules (J)
28
What is the unit of force?
Newtons (N)
29
What is the unit of distance?
meters (m)
30
What is the unit of the spring constant?
Newtons per meter (N/m)
31
What is the unit of the spring extension?
Metres (m)
32
What is the unit of speed or velocity?
metres per secons (m/s)
33
What are the units of acceleration?
metres per second squared (m/s2)
34
What are the units of momentum?
kilogram metres per second (kg m/s)
35
When a spring is stretched and can then return to its original length it is known as __________ _______________
elastic deformation or elastic behaviour
36
When a spring is stretched and its length is permanently altered it is known as ___________ ____________
Inelastic deformation or inelastic behaviour
37
The limit of proportionallity of a spring is…
the length a spring can be stretched to before it no longer returns to its original length
38
Sketch the Force (y) -Extension (x) curve for stretching a spring from no force to beyond its elastic limit.
teacher to draw on board…
39
The stopping distance of a vehicle is the sum of the …..
thinking and breaking distances
40
The distance a vehicle travels while the driver is reacting is the …
thinking distance
41
The distance a vehicle travels which the driver is breaking is the …
breaking distance
42
Reaction time is…
the time it takes a driver to react
43
A typical reaction time is …
0.2-0.9 s
44
Factors which influence reaction time are…
tiredness, drug, alcohol, distractions
45
Fctors which affect breaking distance are …
weather conditions, conditions of breaks and tyres
46
Both thinking and breaking distance are affected by which factor?
speed of vehicle
47
The greater the speed of a vehicle, the _________ the force required to stop the vehicle
greater
48
The distance and object moves and the direction in which it moves is known as the _________
displacement
49
The speed of an object in a particular derection is its ___________
velocity
50
The change of an objects speed in a given time is the _________
acceleration
51
Acceleration of falling objects close to the earth is ________
9.8 m/s2
52
When the force moving an object is balanced by frictional forces it is moving at its _____________ _____________
terminal velocity
53
On a distance time graph a straight line represents…
constant speed
54
On a distance time graph a upward curve represents…
acceleration
55
On a distance time graph a curved line becoming horizontal represents…
decelleration
56
On a distance time graph a horizontal line represents…
stationary
57
On a distance time graph the gradient is used to calculate the …
speed or velocity
58
On a velocity time graph an upwards straight line represents …
acceleration
59
On a velocity time graph a downwards straight line represents …
decelleration
60
On a velocity time graph a horizontal line represents …
constant speed
61
On a velocity time graph a horizontal line along the x-axis represents…
stationary object
62
On a velocity time graph, when the line falls below the x-axis it indicates that the object is …
moving backwards
63
Calcuating the gradient of a velocity time graph gives the …
acceleration
64
Calculating the area under a velocity time graph gives the …
distance travelled
65
A typical walking speed is …
1.5 m/s
66
A typical running speed is …
3 m/s
67
A typical cycling speed is …
6 m/s
68
Sound in air travels at …
330 m/s
69
State Newton's First Law
The velocity of an object will only change if a resultant force is acting on the object.
70
If balanced forces act on a moving object it will …
continue to travel at a constant speed
71
If balanced forces act on a stationary object it will …
remain stationary
72
State Newton's Second Law
Force = mass x acceleration (The acceleration of an object is proportional to the resultant force acting on the object, and inversley proportional to the mass of the object)
73
State Newton's Third Law
Whenever two objects interact, the forces they exert on each other are equal and opposite
74
The tendency of objects to continue in their state of rest or of uniform motion is known as …
inertia