Answer:1.27
Explanation:
Given
incident angle 
refracted angle 
Suppose
is the refractive index of material then using Snell's law we can write

where
=refractive index of air



Answer:
1800 m/
Explanation:
We know this because of Newton's first law,
, which shows us that the force on an object is equal to its mass times the acceleration it recieves. This means that taking our values of 900N and 0.5kg, and plugging them in,

This is honestly a little strange because the force applied and the acceleration seem ridiculous, and a little strange for an answer. Either the values are not meant to be nearly close to reality, or you made a typo.
Answer:
22 revolutions
Explanation:
2 rev/s = 2*(2π rad/rev) = 12.57 rad/s
The angular acceleration when it starting

The angular acceleration when it stopping:

The angular distance it covers when starting from rest:


The angular distance it covers when coming to complete stop:


So the total angular distance it covers within 22 s is 62.8 + 75.4 = 138.23 rad or 138.23 / (2π) = 22 revolutions
Answer:
B
Explanation:
Speed is the magnitude of the velocity vector, so it can never be negative.
Radiation is a type of heat transfer wherein there is no need for medium or media through which the heat will flow. Consequently, the radiation waves are able to travel through vacuum. The best observation as evidence to conclude that heat is indeed transferred by radiation is the increase of temperature of the receiving body.