Answer
The refracted wave must obey Snell's equation
Ni sin θi = Nr sin θr
If Nr differs from Ni then sin θr will differ from sin θi
If the wave originates from point A and ends at point B then Snell's Law shows that the time for light to get from point A to point B is a minimum.
Which were difficulties that the builders of the transcontinental railroad found ways to overcome? Select all the choices that apply.
Answer: Out of all the options presented above the ones that represent the difficulties that the builders of the transcontinental railroad found ways to overcome are answer choices A) providing supplies to build the tracks and support the workers and B) natural barriers such as mountains, rivers, and forests. It was also the same reason why the transcontinental railroad was being constructed. It would help the transportation of if this is hitory i dont know what subject this is but if its history heres the answers
Answer:
Yes, it is. The summers and the winters are getting warmer. Also in cold places like Alaska, the temperatures are rising.
Explanation:
I think the answer is B because I did this before
a) 
, 
The work done by the student in each trial is equal to the gravitational potential energy gained by the student:
where
m = 68 kg is the mass of the student
g = 9.8 m/s^2 is the acceleration of gravity
is the gain in height of the student
For the first student, 
, so the work done is
The second student runs up to the same height (3.5 m), so the work done by the second student is the same:
2) 
, 
The power exerted by each student is given by
where
W is the work done
t is the time taken
For the first student, and 
, so the power exerted is
For the second student, 
and 
, so the power exerted is
