Consider the x - t plane of an inertial observer in sr. a certain uniformly accelerated observer wishes to set up an orthonormal coordinate system. by exer. 21, 2.9, his world line is t(lambda) = a sinh lambda, x(lambda) = a cosh lambda, (5.96) where a is a constant and ax is his proper time (clock time on his wrist watch). show that the spacelike line described by eq. (5.96) with a as the variable parameter and a fixed is orthogonal to his world line where they intersect. changing a in eq. (5.96) then generates a family of such lines. show that eq. (5.96) defines a transformation from coordinates (t, x) to coordinates (a, a), which form an orthogonal coordinate system. draw these coordinates and show that they cover only one half of the original t x plane. show that the coordinates are bad on the lines so they really cover two disjoint quadrants, find the metric tensor and all the christoffel symbols in this coordinate system. this observer will do a perfectly good job, provided that he always uses christoffel symbols appropriately and sticks to events in his quadrant. in this sense, sr admits accelerated observers. the right-hand quadrant in these coordinates is sometimes called rindler space, and the boundary lines x=plusminus t bear some resemblance to the black-hole horizons we will study later.

i would think it's food chain

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.

this could be newton#'s law of cooling. the cooling curve is exponential

at right angles to each other