Eva is in a closed, dark room. She uses her arm muscles to turn on a lamp. When she moves her hand closer to the lamp, the light heats her hand. The light bounces off the pages of a book and into her eyes. If this room is a closed system, what happens to the total amount of energy in the room? A. It remains constant. B. It decreases. C. It increases. D. It increases, then decreases.
@Greg_D
Even if the room is a closed system, i think energy is getting in to the room trough the lamp, since i guess the source of electric power is not inside the room.... with this assumtion made... energy increases at least until she turns the lamp off :)
@jakematt24 , What do you think it should be?
i was thinking a or b to be honest
if it is a closed system, energy can't go out.
good point
Since the room is a closed system, no energy can escape from inside the room and no energy can enter from outside the room. Since, the lamp is inside the room and is constantly emitting energy in form of heat and light and no energy can escape outside, the energy inside the room will continue increasing.
ok, thanks
exactly!
@Abhisar can you give @Greg_D a medal plz
can u help w/ one more
Which statement correctly describes the gravitational potential energy of the pendulum based on this diagram? A. It is greatest when the bob is in the rest position. B. It is greatest when the bob is at its maximum amplitude. C. It is greatest at 25% of the period length. D. It is greatest at the point where the arm meets the pivot point.
Have already given one :-)
One question per post (-:
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