A commuter has to cross a train track each day on the way to work. The probability of having to wait for a train is .2. If she h
1 answer:
Answer:
21 minutes
Step-by-step explanation:
Her expected commute time is given by the probability of having to wait for the train (0.2) multiplied by the commute time in this scenario (25 min), added to the probability of not having to wait for the train (1 - 0.2) multiplied by the commute time in this scenario (20 min). The expected commute time is:
Her expected commute time is 21 minutes.
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Answer:
<h2>Outer Electric Field is 11250 N/C.</h2><h2>Inner Electric Field is -10000 N/C.</h2>Step-by-step explanation:
First of all, we need to read carefully and analyse the problem. As you can see, is an electrical subject, and it's given surface charge densities and radius.
So, to calculate electric fields, we need to find the proper equation to do so: ; as you can see, first we need to find the charges.
We can find all charges using the surface charge densities, because it has the next relation: ; which indicates that charge density is the amount of charge per area. But, there's a problem, we don't have areas, so we have to calculate them first with this relation:
; which gives us the surface of a sphere.
The inner surface:
The outer surface:
Now we can calculate the charges,
Inner charge:
Outer charge:
Then, we are able to calculate both fields:
Inner field:
Outer field:
The directions that field have is opposite each other, the inner one has an inside direction, and the outer electric field has an outside direction.