Answer:
0.002833 sec
Explanation:
Speed of light in vacuum is 
Given distance = 850 km = 850×1000=850000 m
We have to calculate the time that light take to travel the distance 850 km
Time 
So the time taken by light to travel 850 km is 0.002833 sec
Answer:
11700j
Explanation:
add the two because the plate has to maintain the temp.
2700+9000=11700
Answer:

Explanation:
The momentum change is defined as:

Taking the downward motion as negative and the upward motion as positive, we have:

Replacing (2) and (3) in (1):

Answer:
The quantity of electrons that flows past a given point is 3.0 C.
Explanation:
An electric current (I) is the ratio of the quantity of charges (Q) that flows through a point to the time taken (t).
i.e I = 
It is measured in Ampere's by the use of an ammeter in the laboratory. The quantity of charge that flow through a given point is measured in Coulombs, while time is measured in seconds.
Given that; I = 1.5A and t = 2s, find Q.
Q = It
= 1.5 × 2
= 3.0 C
The quantity of electrons that flows past a given point is 3.0 C.