Hey there!
The answer is C
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Answer:
2. B
3. A
4. C
5. B
6. A
Explanation:
2. Sound waves use vibrating molecules to move. With this being said, sound waves would travel best through dense materials, and would travel worst in empty materials, like space. Using this information, you can infer that B would be the answer because water is denser than air and water is the densest material on that list.
3. The speed of the wave is equal to the frequency times the wavelength. Since it has a wavelength of 100 meter and 20 Hertz, the speed would 2000 m/s
4. Like noted in question 2, sound waves travel best in dense materials. Rock is the densest material in that last.
5. By looking at the chart, you can see that the speed increases by 4 m/s when the temperature increases by 10. Using simple division, you could determine that the speed would go up by 2 m/s since the jump between 15 degrees and 20 degrees is 5, which is half of 10, making the speed half of 4.
6. The speed would decrease because, like stated above, sound travels best through dense materials. Since rock is denser than air, the speed would decrease as it leaves.
This one is simple :)
use the equation F = ma and then re-arrange for a.
a = F / m
But there is a trick, so be careful. the question gives you wind resistance. Simply subtract the wind resistance from the thrust of the rocket to get the net force upward.
So,
Answer:
a periscope use total internal reflection to allow us to see things
the reflection happens at 45°
Explanation:
