Answer:
255 Hz
Explanation:
With 5 beats per second with the 250 Hz fork, we know the unknown fork is either 250 - 5 = 245Hz or 250 + 5 = 255 Hz
With 15 beats per second with the 270 Hz fork, we know the unknown fork is either 270 - 15 = 255Hz or 270 + 15 = 285 Hz (most people would have a hard time discerning 15 beats per second... 5 per second is hard enough)
As 255 is the common frequency, it is the one selected.
As we know that :

Power, is in Meter. So divide focal length by 100

Answer:
When there is wind it takes longer
Explanation:
With no wind, the round trip time is

When we have a constant wind speed w

comparing the reciprocal times;

This means that t1 is smaller than t2, ergo, it takes longer with wind
Answer:
Time zone is one important factor in difference in location and this in turn affects the result of the resolution and rotation of shadow produced from the sun or other illumination.
Therefore someone at a place might see a clear large shadow due to shinny sun reflection and another a small or dull Shadow at same time if the intensity of the sun or lighting source is going down.
Explanation:
The closer a body/object is to a lighting source the larger the shadow it produces, and the farther the body the smaller the shadow produced.