Semester 2 Final Flashcards
what is the unit for power?
watts
What is the unit for work and energy?
Joules
List the six simple machines:
lever, wedge, pulley, incline plane, wheel and axle, screw
Define input force
amount of effort exerted on a simple machine to make it a complete task
Define output force
force exerted on an object by a simple machine
Define input distance
length of the sloped surface of the ramp
Define output distance
height of the ramp, or the vertical distance the object is raised
Define kinetic energy
the energy associated with motion
Define potential energy
energy that is stored due to interactions between objects in a system
Define thermal energy
the sum of the kinetic energy and potential energy in a system
Define gravitational potential energy; equation?
the energy stored due to gravity; GPE=mgh
Define elastic potential energy
stored energy due to the pulled string and bent bow due to an object’s shape
Why must the biggest hill in a roller coaster be the first hill?
Friction and drag immediately begin to rob the roller coaster car of energy
Define entropy
measure of dispersal energy
Define and give an example of a transverse wave
particles in the medium perpendicular to the direction of the waves travel (ripples on the surface of water)
Define and give an example of a longitudinal wave
particles parallel to the direction of waves travel (sound waves)
What is the equation for wavelength and what is it measured in?
λ=v/f– meters
The speed of a sound wave depends on __________. The loudness of a sound wave depends on __________________. The pitch of a sound wave depends on ____________________.
the medium, amplitude, frequency
What causes sound waves?
Sound waves are created by object variations and produced pressure waves. The pressure wave disturbs the particles and the vibrating object moves in one direction and compresses the air directly in front of it
Define amplitude
the motion of the maximum distance the object moves from the equilibrium position
Define crest
the high point of a transverse wave
Define decibel
common unit of measurement for sound level; dB; power and intensity of sound waves
Define energy
the ability of an object to produce a change in itself or surroundings
Define frequency and what is it measured in?
the number of waves produces per unit of time; hertz
Define inclined plane
a slope surface used to raise heavy bodies
Define lever
a simple machine made of a rigid beam and a fulcrum
Define pitch
the highness or lowness of a sound; depending on frequency of vibration
Define power
the rate of doing work
Define screw
a simple machine which appears like an inclined plane around a rod with a pointed tip
Define pulley
a mechanism compost by wheel and rope used to lift heavy object onto tall heights
Define simple machine
a device that makes tasks easier by changing either the magnitude or the direction of the applied force
Define wave
a disturbance that carries energy through matter or space; transfers energy w/o transferring matter
Define wavelength
shortest distance between points on a wave where the wave pattern repeats itself
Define wedge
a simple machine that has two inclined planes and uses its sharp edge in splitting the objects
Define wheel and axle
the assembly forced by two disks, or cylinders, of different diameters mounted so they rotate together around the same axis
Define work
transfer of energy that occurs when a force is applied through a distance
How do airbags reduce injuries?
they increase the time, thereby reducing force
Which of the following simple machines is found in a pair of scissors?
lever
A detected change in the frequency of a sound due to a moving source or a moving observer is _____________
the Doppler Effect
Sound is produced when there are___________
oscillations in air pressure
A description of a rule of nature is a ______________________
scientific law
A hypothesis can best be defined as a____________________
prediction
The amount of time it takes to complete one complete cycle is the _______________
period
A ____________ is a material with zero resistance
superconductor
In a _______________, there is only one path for the current to flow
series connection
Who was the narrator of the Cosmos episode titled “Electric Boy”
Neil deGrasse Tyson
Who is the “Electric Boy”
Michael Faraday
Current is measure in ______
amperes
A light year equals what distance? Answer should be in both km and miles
A light year equals 9.46 x 10^12 km and 5.88 x 10^12 miles
What event began the universe?
the Big Bang
A constellation’s changing position in the sky, at the same time of the evening, over a period of several weeks is evidence that _____________
the Earth revolves around the Sun
The telescope that solved the problem of color separation was the ___________
reflecting telescope
The Coriolis Effect provides evidence that __________________
Earth rotates on an axis
Which telescope detects invisible electromagnetic radiation?
a radio telescope
The period between successive full moons is ____________________
a lunar month; 29.5 days
Each of Earth’s standard time zones covers about how many degrees?
15 degrees
A benefit that 20th and 21st century space programs have brought to an area outside of astronomy is ___________________
weather; this information helps scientists make accurate weather predictions days in advance
The right combination of temperature, water, and oxygen_________
supports life on Earth
Kepler’s first law states that planets orbit the sun in paths called_____________________
ellipses
Young Earth formed a core, mantle, and crust in a process called___________
differentiation
Early fresh water oceans became salty when:
rainwater carried dissolved solid rock to the oceans
The two inner planets most alike in size, mass, and density:
Venus and Earth
Kepler’s third law describes the relationship between the average distance of a planet from the sun and the planet’s:
orbital period
Which planet has volcanic regions that may still be active?
Mars
Kepler’s second law states that equal areas are covered in equal amounts of time as an object:
orbits the sun
Which is the following planets had the most complex ring system?
Saturn
The early atmosphere developed when many volcanic eruptions released large amounts of gases in a process called:
outgassing
Tides on Earth are caused by:
Earth’s inertial force and the moon’s gravitational force
When a meteoroid hits Earth, it is called a:
meteorite
The idea that the moon’s development began when a large object collided with Earth is called the:
Giant impact hypothesis
The moon today looks as it did 3 billion years ago because:
the moon cooled more than 3 billion years ago
What are the characteristics of one of the Galilean moons?
Io has active volcanoes, Europa is covered by an ice sheet, Callisto is densely cratered
How long is the average sunspot cycle?
11 years
What is the hottest layer of the sun’s atmosphere called?
corona
Energy is the result of:
nuclear fusion
The temperature of the sun’s core is approximately:
15,000,000 degrees Celsius
What elements make up most of the sun’s mass?
Hydrogen and helium
Which of the following are part of the sun’s atmosphere?
photosphere and chromosphere
Particles thrown off the sun’s corona that can affect Earth’s magnetic field are called:
a coronal mass ejection
Einstein’s equation E=mc^2 helps scientists understand the sun’s energy because the equation:
explains how mass can be converted into huge amounts of energy
The most common element in most stars is:
Hydrogen
Stars appear to move in circular paths through the sky because:
Earth rotates on its axis
A nebula begins the process of becoming a protostar when the nebula:
Begins to shrink and increases its spin
The brightest star in the night sky is:
Sirius
A main sequence star generates energy by fusing:
Hydrogen into helium
The heaviest element formed in the core of a star is :
Iron
The change in position of a nearby star as seen from different points on Earth’s orbit compared with the position of a faraway star is called:
parallax
If the spectrum of a star indicates that the star shines with red light, what is the approximate surface temperature of the star?
less than 3500 degrees Celsius
According to Einstein’s theory of relativity, what does a massive body do to the space around it?
causes it to curve
What do scientists believe will happen to the sun in the next 5 billion years?
The Sun will expand into a reg, giant star, becoming so large that it will engulf Mercury and Venus, and possibly Earth.
Why is an old-main sequence star made of a higher percentage of helium than a young main sequence star?
Older stars have burned through its hydrogen producing larger amount s of helium in the process. Young main sequence stars start by generating energy and fusing hydrogen into helium.
How does the movement of Earth affect the apparent movement of the stars in the sky?
The movement of Earth makes it appear as If the stars are shifting slightly to the west.
If a water hose was used to represent an electrical wire, the water pressure would be analogous to the _________, and the amount of water flowing would be analogous to the ____________
volts, amps
For a worse that obeys Ohm’s law, the resistance of a wire depends on the _________ the wire.
length of
Name three fossil fuels and the other 2 main sources of creating energy.
Coal, natural gas, petroleum
Hydropower and nuclear power
Name 2 alternative energy sources that are being used for creating energy
geothermal, biomass, wind power, solar power
A wave carries ______ through space
energy
What is NOT a part of the human body lever system?
nerve fibers
When you use a hammer to strike a nail, what class lever are you using?
Third
When you use a hammer to remove a nail using the claw, what class lever are you using?
First
What is NOT a way to increase power?
increase time
What is NOT true of machines?
they create energy
Waves produced by banjo strings are ______
longitudinal
Springs that require more force to extend have a :
greater spring constant
What is the difference between S and P waves?
S waves cannot travel through molten liquid rock
In general, the speed of sound is greater in ____ and ____ than in ______
solids, liquids, gases
