Answer:
Consider frames X and Y:
If X sees Y moving to his right then Y must see X moving to his right.
If this is not true then one can choose one frame over the other ( a favored frame and this is not allowed)
First figure shows the object position
Second shows the image position
Third shows the focal length.
Answer:
The wavelength of wave is 7.5 meter.
Given:
Speed of wave = 1500 
Frequency of wave = 200 Hz
To find:
Wavelength of wave = ?
Formula used:
Where 
= wavelength of the wave
v = speed of wave
n = frequency of wave
Solution:
Wavelength of wave is given by,
Where = wavelength of the wave
v = speed of wave
n = frequency of wave
= 7.5 m
The wavelength of wave is 7.5 meter.
<span>The correct answer is C:Waves transfer energy, but not matter. A wave does not move matter in the direction of its propagation. It only transfers energy just like the ocean wave traveling many miles away with the water just moving up and down.</span>
