Form 4 Term 1 Physics Unit 17 Mechanics 2 Flashcards

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1
Q

Acceleration

A

The rate of change in speed is measured in metres per second squared

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2
Q

Deceleration

A

Slowing down or negative acceleration

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3
Q

Displacement

A

Quantity describing the distance from from start of journey to end of journey in a straight line with a direction
Example 50km due north of starting point

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4
Q

Force

A

Is a push or a pull

Unit of force is the NEWTON N

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5
Q

Magnitude

A

The magnitude tells us the size of the vector

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6
Q

Moment

A

A turning force around a pivot - clockwise or counterclockwise

Measure in Newton-metres Nm3 (force and distance)

Force multiplied by the perpendicular distance to a pivot

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7
Q

Stationary

A

Not moving

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8
Q

Velocity

A

The speed an object moves in a particular direction

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9
Q

Gravity

A

The force of attraction between all objects
More mass in an object means the it exerts a larger force of gravity

More mass = exerts more force of gravity

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10
Q

Inversely

A

Two variables are inversely related if one decreases when the other increases

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11
Q

Mass

A

Mass is measured in kilograms KGS

mass of an object is a measure of unwillingness of an object to change its velocity (to accelerate)

Large rock = more mass = hard to make it move quickly / gain velocity

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12
Q

Matter

A

Sub atomic particles

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13
Q

Oppose

A

When one things works against something else to reduce of eliminate effect

Example: an opposing force to a PUSH is a PULL

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14
Q

Frictional force

A

Force that resists one object moving through or over something

Example: air resistance on a car as it drives along (like when hold hand out car window)

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15
Q

Kinetic energy

A

Energy which an object possesses by being in motion

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16
Q

Resultant force

A

The single force that could replace all the other forces acting on an object

Calculated by adding all forces together.

If all forces are equal the resultant force is zero

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17
Q

Surface area

A

The total area of an object

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18
Q

Terminal velocity

A

The max speed of an object - reached when the forces moving on the object are balanced by its frictional forces.

At terminal velocity acceleration is zero (it can’t go any faster it’s at maximum)

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19
Q

Pressure

A

The force per unit

Measured in Pascals PA

20
Q

What does pressure determine ?

A

The effect of a force on a surface

Measures in Pascals - Pa

21
Q

What happens to acceleration at terminal velocity

A

It is at zero - the object has reached its maximum Speed

22
Q

What unit is pressure measured in and what is the symbol

A

Pascal

Pa

23
Q

What unit is force measured in and what is the symbol

A

newtons

N

24
Q

What unit is area measured in and what is the symbol

A

Metres squares

m2

25
Q

What does pressure help to do ?

A

Helps to move blood around the body

Allows organisms to breathe

26
Q

What does bigger surface area mean for pressure

A

Means less presssure when greater surface area
Normal Shoes on snow have lots pressure so sink into snow
Snowshoes have big surface area so they reduce the pressure you exert on the snow so you don’t sink

27
Q

what did robert boyle discover

A

that volume is inversely proportional to pressure (more pressure equals less volume)

he trapped a bubble of an air in a J shaped tube which was caped at one end. poured mercury in and slowly increased the pressure and the air bible got smaller

more pressure causes less volume eg squeeze balloon

28
Q

what is the pressure in the atmosphere at sea level

A

100,000 Pascals (Pa)

29
Q

what did greek scientist archemide discover

A

the physical law of buoyancy

30
Q

what is the Archimedes Can/Eureka can theory?

A

any object immersed in a fluid is acted upon by an upward, or buoyant, force equal to the weight of the fluid displaced by the object.

When an object is dropped into water it will float because of the upward or buoyant force on it

31
Q

pressure and gases

A

the pressure is created by the molecules colliding - the faster they collide the pore pressure and they push outwards

32
Q

if you contain a gas in a confined spaced what happens to pressure

A

it increases as there are more collisions - a balloon expands outwards

33
Q

what is the difference between velocity and speed

A

velocity is speed in a direction

34
Q

what happens to atmospheric pressure as you go higher

A

in increases because as altitude increases

  • the number of air molecules decrees
  • the weight of the air decreases
  • less air above the surface
35
Q

what is the relationship between pressure and volume

A

more pressure means less volume eg squeeze a balloon

36
Q

what is density

A

how closely packed particles are in a solid liquid or gas

37
Q

how do you calculate density

A

mass divided by volume

38
Q

do heavier items have more or less density

A

more as the particles re more closely packed in the same volume

39
Q

what is the unit for density

A

kg/m3 or g/gm3

40
Q

is water or ice more dense ?

A

about the same as same number of particles the space it takes up. ice cube and water take same space.
When turn water to steam it has less density as particles get further apart

41
Q

forces are usually

A

a push or pull

42
Q

force is measure in what unit

A

Newtons

43
Q

what is turning force and what unit is it measured it

A

a Moment - measure in Newton metres (force and distance)

44
Q

when you draw graphs to show speed/distance etc what 4 things must you include

A

units
line or curve
points
labels

45
Q

on velocity time graph how would you find displacement

A

o the areas under the line

46
Q

Newtons main law of motion

A

every action has an equal and opposite reaction

that means - forces act in pairs