Question

d Quick physics review questions! Best answer gets medal!! Please help quickly! : Which of these is an experiment generally regarded as being first carried out by James Joule?
observing that objects increase in temperature when heated with fire

showing that friction slows down the motion of objects

measuring the temperature increase of water from doing work stirring it

testing the mechanical advantage of pulleys

What did Joule's experiment directly show?

The temperature of water increases from the addition of heat.

Heat is a form of energy.

Heat can be neither created nor destroyed.

Electromagnetic radiation has energy.

Answer 1

I think the answers are c and c

Answer 2

c and b *

Answer 3

@UnkleRhaukus

Answer 4

I agree, c and b. I just checked my textbook.

Answer 5

yeps

Answer 6

awesome! 2 more questions?

Answer 7

ok, but can you label a-d?

Answer 8

yep sorry about that

Answer 9

What kind of energy is the source of the light and heat produced by a burning log?

a chemical energy

b kinetic energy

c gravitational energy

d electrical energy



Which form of energy is responsible for the primary energy output of the sun and other stars?
a chemical energy
b nuclear energy
c mechanical energy
d electromagnetic energy

Answer 10

I'm not sure on the first but the second I think might be b?

Answer 11

i'm going to take a guess here.
I think the first one is a chemical reaction since the wood eventually becomes ash so (a)

I don't think it's a nuclear reaction since nuclear reactions are usually with Uranium and Plutonium. I do know that the light generated by the sun is an electromagnetic wave.

Answer 12

@LastDayWork

Answer 13

combustion is chemical reaction, yes

hydrogen fusion [not fission] is nuclear, yes

Answer 14

so it would be a and b?

Answer 15

√√

Answer 16

oh one last question I'd like to verify with you guys! My answer is 8,000 J not sure though. : A particular engine takes in 10,000 J of heat, does 2,000 J of work, and as it runs discharges heat. Its own energy is the same when it has finished as when it started. How much heat did it discharge if this is a closed system?

Answer 17

yeah its just conservation of energy

Answer 18

isn't the conservation of energy
E=Q+W?

Answer 19

E= Q+W ?

Answer 20

sorry don't think we've covered that in class yet

Answer 21

W is work,
Q is heat,

Answer 22

it's actually from mechanics, if you're in thermodynamics, you definitely covered that equation already

Answer 23

ok so it would be 10,000 = 2,000 + heat
10,000 - 2,000 = heat?

Answer 24

yeah you got it

Answer 25

so 8,000 J is correct?

Answer 26

do i really need to confirm that again

Answer 27

the part that had me unsure was because it said 10,000J of heat instead of 10000J of energy

Answer 28

oh

Answer 29

well what do u think the answer would be?

Answer 30

if the other person is sure, then that's fine with me;
I don't want to cause unnecessary confusion

Answer 31

oh ok just wanted to be sure because sometimes there may be two ways to a question but I'll go with 8,000 J

Answer 32

heat is a form of energy as Joule showed above