Jenna M

An elevator has a mass of 770 kg, not including passengers. The elevator is designed to ascend, at constant speed, a vertical distance of 20.0 m (five floors) in 15.0 s and it is driven by a motor that can provide up to 36 hp to the elevator. What is the maximum number of passengers that can ride in the elevator? Assume that an average passenger has a mass of 66.0 kg.

The total consumption of electrical energy in the United States is about 1.0 1019 joules per year.

(a) What is the average rate of electrical energy consumption?

W

(b) If the population of the United States is 260 million, what is the average rate of electrical energy per person?

W

(c) The sun transfers energy to the earth by radiation at a rate of approximately 1.0 kW per square meter to surface. If this energy could be collected and converted to electrical energy with 60% efficiency, how great an area would be required to collect the electrical energy used by the United States?

km^2

A baseball is thrown from the roof of a 30.0 m building with an initial velocity of magnitude 16.0 m/s and directed at an angle of 53.1° above the horizontal.

(a) What is the speed of the ball just before it strikes the ground? Use energy methods and ignore air resistance.

m/s

(b) What is the answer for part (a) if the initial velocity is at an angle 53.1° below the horizontal?

m/s

(c) If the effects of air resistance are included, will part (a) or (b) give a higher speed? Choose one:

No, the air resistance would have the same effect on the two balls and they would be slowed the same amount.

Pendulum. A small rock with mass 0.20 kg is fastened to a massless string with length 0.50 m to form a pendulum. The pendulum is swinging so as to make a maximum angle of 45° with the vertical. Air resistance is negligible.

(a) What is the speed of the rock when the string passes through the vertical position?

m/s

(b) What is the tension in the string when it makes an angle of 45° with the vertical?

N

(c) What is the tension in the string as it passes through the vertical?

N

A force of 500 N stretches a certain spring a distance of 0.240 m. What is the potential energy of the spring when a 65.0 kg mass hangs vertically from it?

J

A spring of negligible mass has force constant k = 1300 N/m.

(a) How far must the spring be compressed for 3.90 J of potential energy to be stored in it?

m

(b) You place the spring vertically with one end on the floor. You then drop a 1.70 kg book onto it from a height of 0.60 m above the top of the spring. Find the maximum distance the spring will be compressed.

m

A 2.00 kg piece of cheese is placed on a vertical spring of negligible mass and force constant k = 1600 N/m that is compressed 20.0 cm. When the spring is released, how high does the cheese rise from this initial position? (The cheese and the spring are not attached.)

m

You are asked to design a spring that will give a 1080 kg satellite a speed of 3.50 m/s relative to an orbiting space shuttle. Your spring is to give the satellite a maximum acceleration of 5.00g. The spring's mass, the recoil kinetic energy of the shuttle, and changes in gravitational potential energy will all be negligible.

(a) What must the force constant of the spring be?

N/m

(b) What distance must the spring be compressed?

m

A 0.75 kg book moves vertically upward a distance of 12 m, and then vertically downward 12 m, returning to its initial position.

(a) How much work is done by gravity during the upward motion of the book?

J

(b) How much work is done by gravity during the downward motion of the book?

J

(c) What is the total work done on the book by gravity during the complete round trip?

J

(d) On the basis of your answer to part (c), would you say that the gravitational force is conservative or nonconservative?

The gravitational force is non conservative.

The gravitational force is conservative.

Explain.

A 0.75 kg book slides on a horizontal table. The kinetic friction force on the book has magnitude 1.9 N.

(a) How much work is done on the book by friction during a displacement of 5.0 m to the left?

J

(b) The book now slides 5.0 m to the right, returning to its starting point. During this second 5.0 m displacement, how much work is done on the book by friction?

J

(c) What is the total work done on the book by friction during the complete round trip?

J

(d) On the basis of your answer to part (c),would you say that the friction force is conservative or nonconservative?

Friction is not a conservative force.

Friction is a conservative force.

A wooden rod of negligible mass and length 84.0 cm is pivoted about a horizontal axis through its center. A white rat with mass 0.800 kg clings to one end of the stick, and a mouse with mass 0.200 kg clings to the other end. The system is released from rest with the rod horizontal. If the animals can manage to hold on, what are their speeds

What is the shape formed when the area between the functions xy=8 and x+y=9 is rotated around the x-axis? What do the the cross sectional slices look like? What are the expressions for the area of fthe cross sectional slice at any point x in the interval of the rotation?

A chemist needs to prepare 425 mL of a .315 M solution of NaOH from a 1.25 M solution of NaOH. How many mL of 1.25 M NaOH must be diluted with water to prepare the solution?

Thanks so much, and if you have anymore time it would be great if you could help me with these questions too:

Calculate the vapor pressure of a solution of 3.15 g of aspirin (C9H8O4) in a 75.0 g of methanol (CH3OH) at 21.2 degrees C. Pure methanol has a vapor pressure of 101 torr at this temperature. Aspirin is a non-volatile, non-electrolyte.

Salt is added to water and the mixture is stirred until no more salt dissolves. the salt that does not dissolve is allowed to settle out. What happens to the concentration of the salt in the solution if the water evaporates until the volume of the solution is half the original volume? (assume temperature is constant). Explain your answer.

Unfortunately, I had to miss a week of school due to the fact that i contracted swine flu. So, it would be extremely helpful if someone could answer the questions from a worksheet my teacher gave me. Here they are:

Directions: For each question, write down all plant groups (green algae, mosses, ferns, gymnosperms, angiosperms,monocots, dicots) that apply.

1. Tiny plants that live in moist places, that transport water by diffusion.

2. These organisms can be used to treat wounds and increase water holding capacity of soils.

3. These organisms differ from mosses in that they reproduce by seeds.

4. These organisms differ from mosses in that they have transport tubes for water.

5. All evergreens and ginkgoes are in this group.

6. These organisms are also called bryophytes.

7. These organisms have vascular tissue.

8. These organisms have fronds.

9. These organisms do not have true roots.

10. These organisms do not have true leaves.

11. This phylum is the most diverse.

Unfortunately, I had to miss a week of school due to the fact that i contracted swine flu. So, it would be extremely helpful if someone could answer the questions from a worksheet my teacher gave me. Here they are:

Directions: For each question, write down all plant groups (green algae, mosses, ferns, gymnosperms, angiosperms,monocots, dicots) that apply.

1. Tiny plants that live in moist places, that transport water by diffusion.

2. These organisms can be used to treat wounds and increase water holding capacity of soils.

3. These organisms differ from mosses in that they reproduce by seeds.

4. These organisms differ from mosses in that they have transport tubes for water.

5. All evergreens and ginkgoes are in this group.

6. These organisms are also called bryophytes.

7. These organisms have vascular tissue.

8. These organisms have fronds.

9. These organisms do not have true roots.

10. These organisms do not have true leaves.

11. This phylum is the most diverse.

is this right?

how many oxygen atoms are in 3.5 moles of oxygen gas?

2.107 X 10^24 atoms

also if you can:

What is the volume of a balloon containing 3.5 moles of helim?

What is the mass of 3.5 moles of water?

Borazine has the empirical formula BNH2 and a molar mass of 80.50 g. What is its molecular formula?

An organic acid was found to contain the following percentages by mass: 63.15% C, 5.30%H, and 31.55% O. What is its empirical formula?

How many moles of silver ions Ag+ are there in Ag2CO3

Thanks so much!

A vector has initial point (3,1,6) and terminal point (-2,1,-8).

a) Write the vector in component form

b) Find the magnitude of the vector

c) Find the unit vector in the direction of the vector

d) Find the unit vector in the direction opposite that of the vector.

Thanks so much!

recursive: a1=1

ak+1 = 2 - ak

I've figured out the first five terms (3,-1,3,-1,3) but i cant figure out the explicit equation...

Also, if your computer has the capability to write it, please do. Additionally, how do you say "to honor"? Like to honor someone...

Thanks

Also, would a dro in blood pH speed up or slow down you rate of breathing in order to maintain homeostasis.

If you know these, that would be great too:

State whether each of the following pertains to inhalation or exhalation:

a) the diaphragm contracts

b) the rib cage expands

c) the volume of the rib cage decreases

d) air is forced out of the lungs

e) air pressure in alveoli is less that that of the atmosphere

a) Iron deficiency can cause a decrease in the number of red blood cells.

b)cystic fibrosis is an inherited disease in which the surfaces of the alveoli become coated with thick, sticky mucus.

c) Carbon monoxide in cigarette smoke takes the place of oxygen in the hemoglobin molecules.

Please name all of the structure involved along the way (including the chambers in the heart as well as venules and arterioles).

thanks so much

Also why is the coronary artery so important, and what would happen if it was blocked?

thanks..

so basically I've narrowed it done to three: RocketReview, Princeton Review, and the Official SAT prep book

From what I've read, the RocketReview book seems very good, especially because it caters to the new SAT test. However, since it's relevantly new, not many people know about it and I've heard it has mistakes. Almost everyone I've talked to recommends the Princeton Review book, but it seems like RocketReview may have some new, innovative tips that the Princeton Review lacks. Overall, however, the Princeton Review seems like a safe choice. Lastly, there is the Official SAT prep book. To me, it makes a lot of sense to buy this one, because the practice tests are written by the same people who write the real tests. Yet, I have not heard to many good things about this book. It is probably my third choice as of now. It would be so helpful if you could take some time to recommend a book to me, and also to tell me why that book is a good choice or why the others are bad.

(single as in you are not in a relationship...)

When I plug in my external hard drive (its a WD Passport) my computer detects the hardware and runs the autoplay. However when I click on Local Disk (:F) on my computer, it says that the disk isn't formatted, and prompts me to format it. I know that formatting it will delete everything that I have saved on the hard drive, so I don't want to do that. This just started happening all of a sudden, it has worked ever since I got it. I made no major changes to my computer from the last time that the hard drive worked to now. Please help!! Thanks soo much..

could someone please tell me some themes motifs and/or symbols from this book? thanks SO much!

If so, can someone tell me how I would distinguish that just by looking at the equation. Thanks!