Physics, 15.07.2019 07:30 nhu78

Two wires when connected in series have an equivalent resistance of 18ohm nd when in parallel an equivalent resistance of 4ohm find their resistance

Answers: 1

Show answers

Answers

Givens
r1 + r2 = 18
r1*r2 / (r1 + r2) = 4

Sub and Solve
There are many ways to proceed. I like to find r1*r2 and that simplifies things.

substitute 18 for r1 + r2
r1*r2 / 18 = 4 multiply by 18
r1 * r2 = 4 * 18
r1 * r2 = 72

Now you can set up a quadratic. Using r1 + r2 = 18, solve for r1
r1 = 18 - r2

Substitute into r1*r2 = 72
r2*(18 - r2) = 72 Remove the brackets.
18r2 - (r2)^2 = 72 Bring the left side over to the right side.
0 = (r2)^2 - 18r^2 + 72

This factors
(r2 - 12)(r2 - 6) = 0
r2 - 12 = 0
r2 = 12
or
r2 - 6 = 0
r2 = 6

r1*r2 = 72
r1*12 = 72
r1 = 72 / 12
r1 = 6

r1 = 12 when r2 = 6.

Answers
r1 = 12
r2 = 6

or

r1 = 6
r2 = 12

Answer from: Quest

elly's long hair:

a. if the salon only takes cash, then this isn't the problem. it doesn't matter how much she has in her checking account. she can't get a haircut until she has the cash.

b. if she has overdraft protection, then there's no problem. she can go ahead and write a check that her account can't cover, then sometime later, pay the bank some outrageous usury for loaning her a few bucks for a few days, but with beautiful hair.

c. if elly has some principles, and doesn't want to write a bad check, then now she has a problem. her desire for the new hairstyle is in conflict with her honesty and integrity.

d. if the bank will not process a check she writes, then even if she had a million $$ in her account, she couldn't use any of it. the amount she has in her account is not the problem. and if i may suggest, she might as well close her checking account, and put the money where it'll work for her. it's not doing her a bit of good in a checking account, since she can't write any checks.

justin can't pay the full balance:

a. he can't even handle the credit limit he has now. under no circumstances should he ask for a higher limit.

b. he can ask for the grace period to be extended. but that's no solution, the bank will almost certainly refuse anyway, and there are much better options. he knew the rules of his credit card when he started using it.

c. he definitely should pay the interest on the balance, plus as much of the balance as he can cover at the same time.

d. he definitely should pay the minimum otherwise they could shut down his card. he should also pay as much more as he possibly can. he should also remember the awkward situation he's in, stop buying stuff on credit that he can't afford, and avoid adding any more debt.

i'd say that justin's best best option isn't on this list of choices. what he has to do: pay as much as he can at least the minimum payment plus as much more as he can and then avoid adding more debt.

Answer from: Quest

1 the 4 is sig

Other questions on the subject: Physics

Physics, 21.06.2019 23:20, pineapplepizaaaaa

Acharge of 8.4x10^-4 c moves at an angle of 35 degrees to a magnetic field that has a field strength of 6.7x10^-3 t. if the magnetic force is 3.5 x10 ^-2 n, how fast is the charge moving?

Answers: 1

continue

Physics, 22.06.2019 03:00, ronniethefun

1. a net force of 100 newton’s is applied to a wagon for 5 seconds. this causes the wagon to undergo a change in momentum of

Answers: 2

continue

Physics, 22.06.2019 09:00, kiarajack456

Why can blue light and yellow light combine to produce white light? question 17 options: they are both primary colors of light. they absorb each other's wavelengths. because blue, yellow, and white are primary colors. they are complementary colors of light.

Answers: 1

continue

Physics, 22.06.2019 14:30, samehajamal1234567

When the displacement of a mass on a spring is 12a the half of the amplitude, what fraction of the mechanical energy is kinetic energy? at what displacement, as a fraction of a, is the mechanical energy half kinetic and half potential?

Answers: 3

continue

You know the right answer?

Two wires when connected in series have an equivalent resistance of 18ohm nd when in parallel an equ...