freshman science A midterm review
a running refrigerator motor
KE
at which point does the ball have the maximum potential energy
a
a certain ocean wave has a frequency of 0.07 Hz and a wavelength of 10 meters. what is the wave's speed
0.7 (10x.07)
A skier at the top of the mountain
PE
which of the stars (a-d) will eventually explode and become a supernova
a and d
what is the final stage of a sun like star
black dwarf
a hairdryer converts ______ energy into ___ thermal energy
electric, thermal
all stars, regardless of their mass, start their lives inside a "stellar nursery" which is known as a cloud of dust and gas known as
nebula
what is meant by luminosity
stars brightness
what is the frequency of a wave that has the speed of 10 m/s and a wavelength of 100 m?
.1 (10/100)
how long ago did our universe form
13.8 billion years ago
all objects with mass exert a gravitational pull, right? well, then why is it that people do not become trapped in each other's gravitational pull?
Gravity depends on the mass of 2 objects as well as the distance between them. the mass of the earth is greater than the mass of a person, which makes makes the force between 2 people
A race-car traveling at its maximum speed
KE
a spring in a paintball machine before it is released
PE
gasoline in a storage tank
PE
the main difference between a low mass star's main sequence stage and high mass stars main sequence stage is
The temperatures on the surface of the star and therefore the color emitted
out of the following which example would have more kinetic every?
a 25 kg mass or a 30 kg mass going 5 m/s ; 30 kg mass going 5 m/s
out of the following which example would have more kinetic every?
a car at rest or a car rolling down a hill ; a car rolling down a hill
What is cosmic microwave background radiation?
a form of electromagnetic radiation which fills the whole universe and is thought to be remnant of the early stages of the universes life
what is a star
a large sphere of gas that makes its own light through nuclear fusion reactions
what kind of energy transformation occurs when your body consumes food
a) chemical—-> thermal b) chemical —-> mechanical (both a & b)
which of the following best explains how we know dark matter exists
all matter has mass, so it has to exert a gravitational pull
which of the following statements best describes the relationship between wavelength and frequency
as a wavelength increases, frequency decreases; as a wavelength decreases, frequency increases
which one of the following particles was NOT present in the first second of the big bang
atom
which types of the stars (a-d) will eventually become a planetary nebula
b and c
list the color of the stars from HOTTEST to COLDEST
blue, white, yellow , red
water flowing from a waterfall before it hits the pond below
both - KE & PE
if the main sequence star was cooler and dimmer than our sun, where would it appear on the graph
bottom right
what effect does the expansion of the universe have on the temperature of the universe
caused it to cool down
a battery uses this form of energy to create electrical energy
chemical
What kind of energy transformation occurs in a natural gas stove
chemical—> thermal
identify the type and color of each star
color- orange/ red ; type- giant
identify the type and color of each star
color- red ;type - supergiant
identify the type and color of each star
color- white ; type dwarf
identify the type and color of each star
color- yellow ; type main sequence
The amount of light that was present after the big bang eventually stretched and cooled as the universe expanded and become a different form of electromagnetic energy known as...
cosmic waves
at which point does the ball have the maximum kinetic energy
d
this is a repulsive force, resulting in the expansion of our universe.
dark energy
why does an ambulance sound differently as it is approaching you compared to as it is driving away?
doppler effect: as it is approaching, the wavelength becomes smaller creating a high pitch. as it is driving away, the wavelength becomes larger, creating a low pitch
energy cannot be converted into any other form
false
our sun will die in a massive explosion known as supper-nova
false
there is more normal matter in the universe than dark matter
false
gravitational potential energy depends on the _____ of an object
height
Which two elements were formed in the early universe?
hydrogen & helium
in really massive stars, once a core of _____ is reached in the red supergiant stage, there is no more fuel left to sustain a star and in less than one second, the entire star will collapse in on itself creating a supernova
iron
what is the standard unit of measurement we use for energy
joule
an 8kg cat is running 4 m/s. how much kinetic energy does it have
ke= 4^2x8/2=16x8/2=128/2= 64J
the life cycle of a star is entirely dependent upon the _______ of the star
mass
the gears of a clock uses what form of energy
mechanical
the muscular (chemical) energy used by your muscles is turned into what form of energy to move a bike
mechanical
which star is denser: a white dwarf or a neutron star?
neutron star
the reason for your answer to the question above is...
neutron stars are produced at the end of the life's cycle of a low mass star and mass isn't important when comparing density
this process fuels a star and occurs during the main sequence stage of a stars life cycle
nuclear fusion
what kind of energy transformation occurs with a solar panel in the roof of a house
radiant —-> electrical
the further away a galaxy is, the faster it is moving away from us which causes the wavelength of light we see from the galaxy to stretch. what color light would we see the most distant galaxies
red
what is the name for a large star with low temperature but high luminosity
red giant
planetary nebulas are formed when the outermost layers of a _______ are expelled out into space
red giants
Which of the following statements is true?
scientists concluded dark matter existed based on the observed speed of stars on the edges of galaxies
a tuning fork uses vibration mechanical energy to create what form of energy
sounds
stars are made up of hydrogen and helium
the first 2 elements created were hydrogen and helium, which come together to form stars
a planet will always rotate in a certain direction unless acted upon by a force great enough. this is due to...
the planets inertia
the answer to the question above is true because
the universe was too hot and dense for atoms to form
A thermometer is used to measure this form of energy
thermal
Where are the hottest and brightest stars on the HR diagram?
top left
dark energy is belived to be causing the expansion of the universe
true
if two stars are the same color and the same distance from earth, but their size is different, the larger star will be brighter
true
nuclear fission from the sun releases nuclear energy
true
supernova are responsible for scattering elements out into space, which were then directly, everything else on those planets
true
out of the following which example would have more kinetic every?
two 10 kg masses, one going 75 m/s, one going 45 m/s ; one going 75 m/s
explain how the following phenomenon provide evidence for the big bang. a) cosmic microwave background radiation
we observe background radiation which was created at the beginning of the universe
red shift
we see that the universe is expanding by observing the red shift of stars and galaxies
Why does an object appear a certain color? for example why is an apple red
when light hits a red object, all colors except for red get absorbed. the wavelength of red light will reflect into our eyes
what is the large star with a high temperature, but low brightness
white dwarf
which of the following stars is no longer undergoing nuclear fusion
white dwarf