Answer:
B.
Step-by-step explanation:
Just took it. Edg 2020. Hope this helps :)
Apparently my answer was unclear the first time?
The flux of <em>F</em> across <em>S</em> is given by the surface integral,

Parameterize <em>S</em> by the vector-valued function <em>r</em>(<em>u</em>, <em>v</em>) defined by

with 0 ≤ <em>u</em> ≤ π/2 and 0 ≤ <em>v</em> ≤ π/2. Then the surface element is
d<em>S</em> = <em>n</em> • d<em>S</em>
where <em>n</em> is the normal vector to the surface. Take it to be

The surface element reduces to


so that it points toward the origin at any point on <em>S</em>.
Then the integral with respect to <em>u</em> and <em>v</em> is



Answer:
2km
Step-by-step explanation:
Answer:
After Two Hours.
Step-by-step explanation:
A simple way to do it is to:
1. Add 50+55, it is equal to 105. This is after one hour, so we know that it's more than this.
2. Add 50+55 to 105, This is after two hours, and we get 210, so we know that it has to be equal to 2 hours.