Amother is her children, of unequal weight, to balance on a seesaw so that they will be able to make it tilt back and forth without the heavier child simply sinking to the ground. given that her heavier child of weight w is sitting a distance l to the left of the pivot, at what distance l1 must she place her second child of weight w on the right side of the pivot to balance the seesaw?
express your answer in terms of l, w, and w.
l1= ?
now consider this problem as a more formal introduction to torque. the torque of each child about the pivot point is the product of the child's weight and the distance of the child (strictly speaking, the child's center of mass) from the pivot. the sign of the torque is positive if it would cause a counterclockwise rotation of the seesaw. the distance is measured perpendicular to the line of force and is called the moment arm.
the concept of torque requires both a force and a specification of the pivot point, emphasized by the first subscript on the torque.
part b
find ? p, w, the torque about the pivot due to the weight w of the smaller child on the seesaw.
express your answer in terms of l1 and w.
tp,
the children's mother wants the seesaw to balance, which means that there can be no angular acceleration about the pivot. the balanced seesaw will then be in equilibrium since it has neither linear acceleration nor rotational acceleration.
for the linear acceleration to be zero, the vector sum of forces acting on the seesaw and children must equal zero.
for the angular acceleration to be zero, the sum of the torques about the pivot must equal zero. this can be written
? i? p, i=0,
where ? p, i is the torque about the pivot due to the i th force.
part c
determine ? i? p, i, the sum of the torques on the seesaw. consider only the torques exerted by the children.
express your answer in terms of w, w, l, and l1.
the child with weight w has an identical twin also of weight w. the two twins now sit on the same side of the seesaw, with one twin a distance l2 from the pivot and the other a distance l3. (figure 2) part d
where should the mother position the child of weight w to balance the seesaw now?
express your answer in terms of l2, l3, w, and w. l=
bad news! when the mother finds the distance l from the previous part it turns out to be greater than lend, the distance from the pivot to the end of the seesaw. hence, even with the child of weight w at the very end of the seesaw the twins exert more torque than the heavier child does. the mother now elects to balance the seesaw by pushing sideways on an ornament (shown in red) that is a height h above the pivot. (figure 3)
part e
with what force in the rightwards direction, fx, should the mother push? note that if you think the force exerted by the mother should be toward the left, your final answer fx should be negative.
express your answer in terms of w, lend, w, l2, l3, and h.
fx=

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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.

-first use of geothermal energy occurred more than 10,000 years ago in north america by american paleo-indians

-the first industrial use of geothermal energy began near pisa, italy in late 18th century

-in 1904, italian scientist piero ginori conti invented the first geothermal electric power plant in which steam was used to generate the power

-with the above experiment, the first geothermal plant in usa started in 1922 with a capacity of 250 kilowatts

-however, in 1946 first ground-source geothermal heat pump installed at commonwealth building in portland, oregon

-during the 1960’s, pacific gas and electric began operation of first large scale geothermal power plant in san francisco, producing 11 megawatts

-in 1973, when oil crisis began many countries began looking for renewable energy sources and by 1980’s geothermal heat pumps (ghp) started gaining popularity in order to reduce heating and cooling costs

-as effect of climate change started showing results, governments of various countries joined hands to fight against it, for which kyoto protocol was signed in japan in 1997, laid out emission targets for rich countries and required that they transfer funds and technology to developing countries, 184 countries have ratified it

hope this