The refractive index is essentially the speed of light through a vacuum (extremely similar to air) divided by the speed of light through given medium.
I also attached some of my physics notes on refraction and that sort of jazz as they may help :)
answer
77.25 N
explanation
(look at picture for free body diagram)
the force on the piano has both vertical and horizontal components, and since the questions asks about the force to lift the piano, we want to find the vertical component
we can use trigonometry where sinA = opposite/hypotenuse
A = 18 degrees
hypotenuse = 250 N
sin18 = opposite (vertical component) / 250
vertical component = sin18 * 250
= 77.25 N
S~ cientists publish their original research in scientific journals, which are fundamentally different from news magazines. The articles in scientific journals are not written by journalists – they are written by scientists. Scientific articles are not sensational stories intended to entertain the reader with an amazing discovery, nor are they news stories intended to summarize recent scientific events, nor even records of every successful and unsuccessful research venture. Instead, scientists write articles to describe their findings to the community in a transparent manner.
Answer:
75ohms
Explanation:
V= IR
V = 1.5volts
I = 0.02A
1.5 = 0.02×R
Making R the subject
R = 1.5/0.02
R = 75ohms
The resistance in the circuit will be 75ohms
