When there was know life on the earth
Answer: 
Explanation:
We know the total diameter of the cell (assumed spherical) is:
Then its total radius 
On the other hand, we know the thickness of the cell wall is 
and its density is the same as water (
).
Since density is the relation between the mass 
and the volume 
:
The mass is: 
(1)
Now if we are talking about this cell as a thin spherical shell, its volume will be:
(2)
Where 
Then:
(3)
(4)
Substituting (4) in (1):
(5)
(6)
Knowing 
and 
:
Answer:
I hope This helps
Explanation:
The majority of oxidation-reduction (redox) reactions share two critical features. One is that a reduction happens in both, while equivalent oxidation occurs; they are combined.
Answer:
Violations. A violation occurs when a player violates the rules in a manner which does not result in physical contact ( e.g. throwing a pass during an approach to the goal line; illegal guarding position by the marker; not establishing a pivot foot after carrying the disc in from out-of-bounds, etc.)
The object of Ultimate Frisbee is to gain points by scoring goals. The disc may only be passed, and a goal is scored when a player successfully passes the disc to a teammate in the end zone which that team is attacking. The team with the most points at the end of the game is declared the winner.
Explanation:
Vert (Vertical) Stack – The most common offensive play in Ultimate Frisbee. The Mailman – An intense offensive tactical maneuver to guarantee a gain of at least 70% of the field. TurboDisc – Can be added to almost any play to ensure max effectiveness.
If contact occurs and the thrower drops the disc, the count stops until the thrower picks up the disc and continues with play. The defensive player will have to back up 5 yards (15 feet) to allow a free throw from the offensive player.
Answer:
The difference between the cost of operating LED and incandescent bulb is $5.1
Explanation:
We are given the cost of electricity that is 12.75 cents per kWh. We want to find out the difference in the operating cost of an incandescent and LED bulb for a time period of 2,000 hours.
Since we are not given the rating of the incandescent bulb and LED bulb, we will assume their ratings.
For a light intensity of 250 Lumens;
The average rating of an LED bulb is approximately 5 Watts.
The average rating of an incandescent bulb is approximately 25 Watts.
Now lets find out the kWh of each bulb.
Energy = Power×Time
For LED bulb:
E = 5×2,000 = 10,000 Wh
Divide by 1000 to convert into kWh
E = 10,000/1000 = 10 kWh
Cost = 12.75×10 = 127.5 cents
Cost = $1.27
For Incandescent bulb:
E = 25×2,000 = 50,000 Wh
Divide by 1000 to convert into kWh
E = 50,000/1000 = 50 kWh
Cost = 12.75×50 = 637.5 cents
Cost = $6.37
Difference in Cost:
Difference = $6.37 - $1.27 = $5.1
Therefore, the difference between the cost of operating LED and incandescent bulb is $5.1.
