Dynamics Flashcards

1
Q

Scaler quantity

A

Fully describes by a magnitude

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2
Q

Vector quantity

A

Fully describes by magnitude and direction

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3
Q

Examples of scaler quantitities

A

Speed
Distance
Time
Energy

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4
Q

Examples of vector quantities

A

Force
Velocity
Displacement
Acceleration

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5
Q

Average speed

A

Total distance divided by total time

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6
Q

Instantaneous speed

A

The speed at a point in time

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7
Q

Experiment to measure average speed

A

Measure the distance between 2 points with an appropriate measuring devise

Start timer as object passes point A

Stop timer as it passes through point B

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8
Q

Experiment to measure insataneous speed

A

A small length of a card is attached to a car

The car passes through a light gate

The timer measure how long it takes the card to pass through the light gate

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9
Q

Experiment to measure acceleration

A

Setup the software to calculate the initial speed at the first light gate and the final speed at the second light gate.

Release the trolley from rest so that it passes through the two light
gates.

Record the time taken for the trolley to pass from the first to the second light gate, using the stopclock.

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10
Q

What does constant speed require

A

Balanced forces

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11
Q

When does turminal velocity occur

A

Resistive forces balance the driving force

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12
Q

Newton’s first raw

A

An object will remain at rest or travel at the same speed, in a straight line, unless an unbalanced force acts on the object.

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13
Q

Newton’s second law

A

An object will accelerate in the same direction as the unbalanced force acting on it.
Force and acceleration are directly proportional

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14
Q

Newton’s third law

A

If A exerts a force on B, B exerts and equal but opposite force on A

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15
Q

Horizontal motion

A

Once the projectile has been fired there are no horizontal forces acting on it, therefore the horizontal velocity is constant.
Falls at a constant speed

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16
Q

Vertical motion

A

The vertical motion can be described as having constant vertical acceleration.

Affected by gravity

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17
Q

Displacement

A

Distance between 2 points in a given direction

18
Q

Acceleration

A

The change in unit time

19
Q

Friction

A

A force that oppose the balance of an object

20
Q

Terminal velocity

A

The constant velocity reached by an objects free fall

21
Q

Why would instantaneous speed have higher results than average speed

A

Instantaneous speed is calculated at max velocity

22
Q

Forces can change

A

Shape
Speed
Direction of object

23
Q

Questions of the weight of objects and people on the moon

A

Gravitational Reid strength numerically is equal to the accerlaeration when frictional forces are ignored

24
Q

Friction on lorry vs car

A

Larry has a higher weight, which means there is more friction acting on it when it turns, lorry weals are designed to keep lorry on the road

25
Friction on skier
Skier need a low friction, This is why they wax their boards
26
Why are to forces acting on an object not cancel each other out
They act on the same object Equal and opposite forces cancel each other out
27
What is acceleration when frictional forces are negligable
9.8ms-2
28
Sky diver
Weight is more than air resistance Terminal velocity- meaning weight and resistance balance falling at a constant speed Parachute goes up meaning there is more air resistance than weight Blanked forces act on skydivers
29
Force on satalight
Forces on a satalight are unbalance as satalight changes direction
30
Feather and hammer dropped on the moon from same height
They hit surface at the same time Moon has no atmosphere meaning ther is no air resistance
31
Calculation of light year
3x108 x 60 x 24 x24 x 365.25
32
If it is slowing down
Negative acceleration
33
Efficiency
How much useful energy is transferred and how much is lost
34
Pendulum
The larger tha mass the more poetail energy Mass has potential energy Starts with potential energy and converts into kinetic energy The pattern continues Does not have enough energy to reach original height Et = Ek + Ep
35
The hier the mass
The lower the acceleration
36
The higher the force
The higher the accleration
37
Forces on a ball
Ball excess coward force on racket | Racket Eckerts and equal but opposite force on ball
38
Object going round earth
The greater the velocity, the greater the distance When it is fired at the right vertical velocity will go around to earth Downwards motion matches curvature of earth Friction less environment Object will orbit earth eg a satalte
39
Vacuum flask
Stop- Stops evaporation Silver - prevents radiation Vacuum - no conduction
40
Less dense
Away from normal
41
Accleration from v-t graph
Gradient