questionary. Flashcards

1
Q

write 4 branches of physics.

A

optics.
thermodynamics.
aerodynamics.
electrodynamics.

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2
Q

formula for velocity,

A

v = d/t

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3
Q

formula for time.

A

t = d/v

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4
Q

difference between vector and scalar.

A

vector — direction and magnitud.

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5
Q

what does ∆ means?

A

delta — difference.

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6
Q

formula for acceleration.

A

a = ∆v / t | ∆v = vf - vi.

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7
Q

what does gravity makes you do if you jump of a plane?

A

fall.

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8
Q

what are the three laws of motion?

A

one ; inertia — tendency of an object to keep moving.
equilibrium — net force = 0.

two ; a = fnet / m | fg = ma

three ; for every action there’s a reaction.

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9
Q

write the eight forces.

A
— weight / gravitational force.
— drag force.
— static force.
— quinetic force.
— normal force.
— tention force.
— net force.
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10
Q

what is equilibrium?

A

fn = 0.

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11
Q

what is a force and what units do we use?

A

when an object has acceleration ; newtons.

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12
Q

how do we calculate the weight of an object?

A

w = mg | m — mass ; g — gravity.

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13
Q

what is the value of gravity?

A

—9.8

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14
Q

units for weight.

A

newtons.

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15
Q

formula for weight.

A

w = mg.

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16
Q

write the simple machines.

A
— wheel n axel.
— lever.
— pulley.
— wedge.
— screw.
— inclined plain.
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17
Q

difference between ‘ima’ and ‘ma’.

A

ima — ideal work.

ma — actual work.

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18
Q

what is kinetic friction?

A

a force that stops something from moving.

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19
Q

what is kinetic energy?

A

the energy of an object moving.

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20
Q

what is potential energy?

A

the energy when an object is on its highest.

pe = mgh.

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21
Q

what is static friction?

A

a force that opposes the initial movement of an object.

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22
Q

what is specific heat and what is water specific heat?

A

amount of energy neede to raise one degree of heat. ; 4180 j/kg.k

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23
Q

what are the laws of thermodynamics?

A

one ; energy can’t be created or destroyed.

two ; everything in nature tens to chaos.

three ; would not be.

24
Q

formula for kinetic energy.

A

ke = 1/2 mr².

25
Q

formula for potential energy.

A

ep = mgh.

26
Q

what is boiling point and freezing point of an object?

A

boiling — temperature which liquid starts transforming in gas.

freezing — temperature which water turns to solid.

27
Q

what is electricity?

A

the flow of energy trough matter.

28
Q

what is heat of evaporation?

A

the energy needed to transform liquid into gas.

29
Q

what is heat of fision?

A

energy needed to melt something.

30
Q

what is a heat engine?

A

a device that turns thermal energy into kinetic energy.

31
Q

the energy tranfered between two objects is called:

A

heat.

32
Q

in which ways can heat be transfered?

A

conduction — contact.
convection — fluid between them.
radiation — waves.

33
Q

what is entropy?

A

the measurement of chaos.

34
Q

what are three basic particles and what are their charges?

A

proton — (+).
electron — (-).
neutron — (normal).

35
Q

what is static electricity?

A

forces that interact with charges that are not moving.

36
Q

formula for force.

A

f = kq1q2 / r² | q — charges.

37
Q

which are different types of magnets?

A

— permanent ; always create magnetic forcefield.

— electricaly-induced ; only creates magnetic forcefield when electricity is applied.

— ferromagnetic ; a metal which when you aline the particles work as a magnet.

38
Q

how can you produce electromagnetism?

A

introducing electricity in a conductor.

39
Q

what are the parts of a transverse wave?

A

— crest ; highest point.
— trough ; lowest point.
— rest ; equilibrium point 0.
— wavelength ; distance from crest to crest.
— amplitude ; distance from crest to rest.

40
Q

define each part of a longitudinal wave.

A

— compression ; when it is more compressed.
— rarefaction ; when it spreads.
— wavelength ; distance between compression to comoression.

41
Q

how does a surface wave moves?

A

circular.

42
Q

which waves deforms matter in order to exist?

A

mechanical wave.

43
Q

explain electromagnetic waves.

A

travels through forcefield.

44
Q

formula for speed.

A

s = d/t.

45
Q

formula for period.

A

t = 1/f | t — period. ; units — seconds.

46
Q

how can you find ⋌?

A

⋌ = v/f | units ; meters.

47
Q

speed of sound at room temperature through the air.

A

343 m/s.

48
Q

what wavelengths can we see?

A

400 — 700 nm.

49
Q

whag frequencies can we hear?

A

20 — 2000 hz.

50
Q

what type of wave is light?

A

electromagnetic.

51
Q

maxwell.

A

proved light was an electromagnetic wave.

52
Q

einstein.

A

proposed light photons.

53
Q

planck.

A

proved wave was particle and wave.

54
Q

what happens to light when it hits another object?

A

— transmitted.
— reflected.
— absorbed.

55
Q

define opaque, translucent, transparent.

A

— opaque ; absorve light.
— translucent ; relfect and transmit light.
— transparent ; transmit almost al the light.

56
Q

relation between luminous flux, illuminance and luminous source

A

all parts of light system.