I really need some help with homework can you please check and help me on the wrong ones?

Question

The second law of governing energy is called the second law of thermodynamics. Which statement below is not part of this law?

a. in any conversion of energy from on form to another there is always some energy lost as "waste heat."

b. heat cannot, of itself, flow from cold to hot: it will, by itself, flow from hot to cold

c. Energy can be created from matter, but not the reverse*****

d. In a self contained world or system, things tend to become more disorganized and randomness tends to increase.

Which of the following is an internal source of energy?

a. hydroecletric energy

b. wind energy

c. radioactive decay*****

d. solar energy

Converting coal to electricity is 30 percent efficient. Converting the electricity to heat in the toaster is 90 percent efficient. Only 10 percent of the heat of the toaster is used to toast the toast. What is the overall efficiency?

a.2.7%

b.27%

c.57%

d.87%*****

e.97%

In a river system, which slope would have the least kinetic energy per kilogram of water?

a. 3 degrees*****

b. 7 degrees

c.12 degrees

d. 15 degrees

If a dam is 200 feet high and a waterfall is 350 feel high, would the water at the base of the waterfall or dam have the greatest kinetic energy per kilogram?

a. waterfall*****

b. dam

Does water gain potential energy as it falls over a waterfall?

a. yes*****

b. no

Is it true that since energy cannot be created nor destroyed, the total energy of the river system remains constant?

a. yes

b. no*****

When water vapors condense into cloud droplets does it release latent heat or absorb it?

a. release

b. absorb*****

Answer 1

Think it through yourself.

The stars are generally right, except for the coal and toaster one. It should be 27%

"

Does water gain potential energy as it falls over a waterfall?

a. yes*****

b. no"

It should be loses potential energy. the potential becomes kinetic.

"Is it true that since energy cannot be created nor destroyed, the total energy of the river system remains constant?

a. yes

b. no*****"

This one is a technicality. Technically yes, but really its no.

Thats why you hope to have a good teacher and you pay attention to what they say.

Answer 2

At least indicate which answer you chose so its not as if we're giving you the answer

Answer 3

uh sorry i dont know.... im only in 7th grade u look like your in highschool. try asking a teacher or friend

Answer 4

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