Section 1 - Motion, Forces and Conservation of Energy Flashcards

1
Q

What are vectors?

A

Quantities with both magnitude and direction.

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2
Q

What are scalars?

A

Quantities with magnitude only.

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3
Q

What are some examples of vector quantities?

A

Force, velocity, displacement, weight, acceleration and momentum.

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4
Q

What are some examples of scalar quantities?

A

Speed, distance, mass, energy, temperature and time.

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5
Q

What is a distance, in physics, defined as?

A

How far an object has moved.

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6
Q

What is displacement, in physics, defined as?

A

The distance and direction in a straight line from an object’s starting point to it’s finishing point.

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7
Q

What is speed, in physics, defined as?

A

Speed is a measure of how fast something is going.

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8
Q

What is velocity, in physics, defined as?

A

How fast something is going and in what direction.

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9
Q

Describe the formula relating (average) speed & time.

A

d=s×t

d = distance
s = (average) speed
t = time
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10
Q

What is acceleration, in physics, defined as?

A

The change in velocity over a certain amount of time.

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11
Q

What is uniform acceleration, in physics, defined as?

A

Speeding up (or slowing down) at a constant rate.

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12
Q

Describe the formula relating acceleration, time and change in velocity.

A

a=(v-u)/t

a = acceleration
v = final velocity
u = initial velocity
t = time
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13
Q

Describe the formula for constant acceleration.

A

v²-u²=2×a×x

v = final velocity
u = initial velocity
a = acceleration
x = distance
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14
Q

Which graph shows how far something has traveled?

A

Distance/Time graphs.

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15
Q

Which graph can have both positive and negative gradients?

A

Velocity/Time graphs.

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16
Q

In a distance/time graph, how can speed be worked out?

A

Speed = gradient = change in y / change in x

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17
Q

In a velocity/time graph, how is distance worked out?

A

By calculating the area under the graph.

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18
Q

What is Isaac Newton’s first law?

A

Every object persists in its state of rest or uniform motion in a straight line unless it is compelled to change that state by forces impressed on it.
Or a still object will not move unless forced to, and a moving object will not stop or change direction unless forced to.

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19
Q

Describe the equation relating resultant force and acceleration.

A

F=m×a

F = resultant force
m = mass
a = acceleration
20
Q

List some safety features used in cars.

A

Seat belts, air bags and crumple zones.

21
Q

What is mass, in physics, defined as?

A

The amount of ‘stuff’ in an object.

22
Q

What is weight, in physics, defined as?

A

Mass with gravity.

23
Q

Describe the equation for weight.

A

W=m×g

W = weight
m = mass
g = gravitational field strength
24
Q

What is Isaac Newton’s second law?

A

Force is equal to the change in momentum per change in time. For a constant mass, force equals mass times acceleration.

25
Q

What is inertia?

A

Inertia is the tendency for motion to remain unchanged.

26
Q

What is Isaac Newton’s third law?

A

For every action, there is an equal and opposite reaction.

27
Q

What is momentum, in physics, defined as?

A

The property that all moving objects have.

28
Q

Describe the equation for momentum.

A

p=m×v

p = momentum
m = mass
v = velocity
29
Q

How, in a closed system, is momentum affected after an event. What is it called.

A

It isn’t, momentum before an event is equal to the momentum after the event. This is known as conservation of momentum.

30
Q

Describe the equation relating force and change in momentum.

A

F=(mv-mu)/t

F = force
m = mass
v = final velocity
u = initial velocity
t = time
31
Q

List the types of Energy Store.

A
Kinetic
Thermal
Chemical
Gravitational Potential
Elastic Potential
Electrostatic
Magnetic
Nuclear
32
Q

Describe the equation for working out the work done by a vehicle’s brakes.

A

1/2×m×v²=F×d

m = vehicle's mass
v = velocity
F = braking force
d = braking distance
33
Q

Describe the equation for kinetic energy.

A

KE=1/2×m×v²

KE = Kinetic Energy
m = mass
v = velocity
34
Q

What is Kinetic Energy?

A

Energy which a body possesses by virtue of being in motion.

35
Q

Describe the equation for a change in Gravitational Potential Energy.

A

ΔGPE=m×g×Δh

ΔGPE = change in Gravitational Potential Energy
m = mass
g = gravitational field strength
Δh = change in height
36
Q

What is Gravitational Potential Energy?

A

Gravitational Potential Energy is energy an object possesses because of its position in a gravitational field.

37
Q

What is Conservation of Energy?

A

The fact that energy can neither be created or destroyed.

38
Q

List the four main methods of energy transfer.

A

Mechanically
Electrically
By heating
By Radiation

39
Q

How is energy made useful?

A

By transferring it into a useful store.

40
Q

Describe the equation for efficiency.

A

Ef=(Eu÷Et)×100
Ef = Efficiency
Eu = Useful energy
Et= Total energy

41
Q

How can efficiency be increased?

A

By removing unwanted energy transfers.

42
Q

How can unwanted energy transfers such as friction and heating be removed?

A

Lubrication reduces energy transfer by friction. Insulation reduces energy transfer by heating.

43
Q

List the types of energy sources. Are they renewable or non-renewable? polluting or non-polluting?

A
Fossil fuels, non-renewable, polluting
Nuclear, non-renewable, polluting
Bio-fuels, renewable, polluting
Wind, renewable, non-polluting
The sun, renewable, non-polluting
Hydro-electric, renewable, non-polluting
Tides, renewable, non-polluting
44
Q

What are current trends in Energy Resource use?

A

Currently we depend on fossil fuels, followed closely by nuclear fuels. However, we are slowly drifting towards renewable, non-polluting fuels like wind and solar.

45
Q

What percentage of the total energy produced in the UK produced using renewable resources?

A

15%

46
Q

What is limiting the current efforts to shift to renewable energy sources?

A

Cost, reliability, aesthetics, research, personal changes.