Surprise 1
(Energy output / energy input ) x 100 = ?
What is energy efficiency ?
how do you get kilowatt hours if you have kilowatts and hours
multiply kilowatts times hours
what is the difference between intermittent and non intermittent energy sources?
intermittent- can only get under specific conditions.
non-intermittent- you can get them whenever.
if a solar panel has a power of 300,000 kw and it needs to generate 5,000,000 kwh of energy, how many hours does the solar panel need to run?
5,000,000/300,000= 16.7 hours
describe how solar panels work using terms photovoltaic affect, photon energy, and p-n junction
the p-n junction separates the charges, kind of like a battery, and the photons blast the p-n junction and using the photovoltaic affect, it sends the charges through a circuit creating a current.
From our knowledge of conservation of energy, as kinetic energy goes up, what do we expect potential energy to do?
to go down
If i have a perfectly perpendicular density of a magnetic field of 100 V and an area of 30m^2, what is my magnetic flux?
What if my area was parallel to the field?
flux = B times A times cos theta
a) 100 X 30 X 1 = 3000
b) 100 X 30 X 0 = 0
give an example of each of the following: mechanical energy, chemical energy, heat energy, electrical, energy and light energy.
(answers may vary)
what do the photon equations tell us:
E = hc / (wavelength)
E = h (frequency)
the energy of a photon comes from the frequency and the wavelength the photon. With a shorter wavelength or higher frequency, the more energy form the photon.
if a velocity is decreasing but still positive, is the acceleration positive or negative?
negative
The equation for energy density is:
energy density = (energy/ volume)
what are two ways to increase energy density
increase energy
decrease volume
describe emission, transmission, reflection, and absorption of light
emission- something gives off light
transmission- light goes through something
reflection- light bounces off something
absorption- light is taken in by something
how do you calculate acceleration with vf and vi and t.
(vf - vi) / t
how do I solve for change in position using the equation below:
rf = ri + (vit) + ((1/2)at2)
rf - ri = (vit) + ((1/2)at2)
What is magnetic flux? How do you calculate it?
how much magnetic field goes through a certain area? Flux = magnetic field times area times the angle
if you have a mass and a height when calculating the change in potential energy of a system on earth, can you calculate work? Explain why or why not.
yes you can. Work is the change in energy, we can calculate the change in potential energy, thus we can calculate the work done on the system.
KE = PE and our initial kinetic energy was 67345 Newton meters (jouoles), what is the tallest height we could climb if we started at an elevation of 0 meters with a mass of 400kg
1.62 meters
how do you convert miles per hour to meters per second
multiply how many meters are in a mile (convert miles to feet and feet to meters) then divide by how many seconds are in an hour (convert hours to minutes and minutes to seconds).
if a photon has a really short wavelength, does it have a high or low energy?
high energy
how does energy most commonly dissipate
through thermal energy or heat
if KE= PE, how do we solve for velocity?
KE = PE
(1/2)mv2 = mgh --> (1/2)v2= gh
v2= 2mgh
v= (2mgh)(1/2)
what are the three ways of transferring energy, explain them
radiation- light waves transfer
convection- the particles move to transfer energy
conduction- the particles don't move, they bump into each other to transfer energy
what is ohms law? Which two main circuit equations does it give us?
I = V/R
P = IV
(energy/ time) = ?
what is power
if Ethan became a cyborg who uses 3,000,000 kilowatt hours of energy a day, what would have to be the power provided by a solar panel connected to the top of his head have to be?
3,000,000 kwh / (24 hours in a day) = 125,000 kilowatts