Answer:
D,B,C,A,C
Explanation:
I believe that is the correct answers but it is unclear. I don't think the key for the second last question would let the current flowing so the bulb would be off.
Answer:
D
Explanation:
The bottom of the mountain is not correct because your trying to stop.
The top is of the mountain is when you gain energy.
The middle is when you have the most kinectic energy.
Answer:
1070 Hz
Explanation:
First, I should point out there might be a typo in the question or the question has inconsistent values. If the tube is 40 cm long, standing waves cannot be produced at 42.5 cm and 58.5 cm lengths. I assume the length is more than the value in the question then. Under this assumption, we proceed as below:
The insert in the tube creates a closed pipe with one end open and the other closed. For a closed pipe, the difference between successive resonances is a half wavelength
.
Hence, we have

.
The speed of a wave is the product of its wavelength and its frequency.



Answer:
Explanation:
density of galaxies would be
times higher which is equal to 50.81.
It means in a cube that today contains one galaxy the size of the Milky Way, we would instead find 50.81 galaxies this size.
You can round this off to 52