Answer:
a)
, b) 
Explanation:
a) The equation for vertical velocity is obtained by deriving the function with respect to time:

The velocities at given instants are, respectivelly:


Answer:
E. The refracted ray is vertically polarized whereas the reflected ray is horizontally polarized.
Explanation:
#PLATOLIVESMATTER
<u>Answer:</u> The final temperature of the solution is 
<u>Explanation:</u>
The amount of heat released by coffee will be absorbed by aluminium spoon.
Thus, 
To calculate the amount of heat released or absorbed, we use the equation:

Also,
..........(1)
where,
q = heat absorbed or released
= mass of aluminium = 39 g
= mass of coffee = 166 g
= final temperature = ?
= temperature of aluminium = 
= temperature of coffee = 
= specific heat of aluminium = 
= specific heat of coffee= 
Putting all the values in equation 1, we get:
![39\times 0.904\times (T_{final}-24)=-[166\times 4.1801\times (T_{final}-83)]](https://tex.z-dn.net/?f=39%5Ctimes%200.904%5Ctimes%20%28T_%7Bfinal%7D-24%29%3D-%5B166%5Ctimes%204.1801%5Ctimes%20%28T_%7Bfinal%7D-83%29%5D)

Hence, the final temperature of the solution is 
Well, there you have a very important principle wrapped up in that question.
There's actually no such thing as a real, actual amount of potential energy.
There's only potential <em><u>relative to some place</u></em>. It's the work you have to do
to lift the object from that reference place to wherever it is now. It's also
the kinetic energy the object would have if it fell down to the reference place
from where it is now.
Here's the formula for potential energy: PE = (mass) x (gravity) x (<em><u>height</u></em><u>)</u> .
So naturally, when you use that formula, you need to decide "height above what ?"
If you're reading a book while you're flying in a passenger jet, the book's PE is
(M x G x 0 meters) relative to your lap, (M x G x 1 meter) relative to the floor of the
plane, (M x G x 10,000 meters) relative to the ground, and maybe (M x G x 25,000 meters)
relative to the bottom of the ocean.
Let's say that gravity is 9.8 m/s² .
Then a 4kg block sitting on the floor has (39.2 x 0 meters) PE relative to the floor
it's sitting on, also (39.2 x 3 meters) relative to the floor that's one floor downstairs,
also (39.2 x 30 meters) relative to 10 floors downstairs, and if it's on the top floor of
the Amoco/Aon Center in Chicago, maybe (39.2 x 345 meters) relative to the floor
in the coffee shop that's off the lobby on the ground floor.