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:
The curl is 
Explanation:
Given the vector function

We can calculate the curl using the definition

Thus for the exercise we will have

So we will get

Working with the partial derivatives we get the curl

Answer:
The number of valence electrons increases to 8 or, the atom gives up loosely held valence electrons.
Explanation:
Please mark brainliest and have a great day!
I think it’s either A or B