# Questions Asked onFebruary 28, 2011

1. ## calc

Show that the equation x^3-15x+c=0 has at most one root in the interval [-2,2].

2. ## physics

A hair dryer uses 10A at 120V. It is used with a transformer in England, where the voltage is 240V. A. What should be the ratio of the turns of the transformer? B. What current will the hair dryer now draw?

3. ## statistics

Susan is taking Western Civilization this semester on a pass/fail basis. The department teaching the course has a history of passing 77% of the students in Western Civilization each term. Let represent the number of times a student takes Western

4. ## physics

A shotputter accelerates a 7.3kg shot from rest to 14m/s. If this motion takes 2.0s what average power was developed?

5. ## math

what is the 10th term in this arithemetic sequence of 2,9,16,23,30?

6. ## Physics

A 1200 kg car rolling on a horizontal surface has spped v= 65 km/h when it strikes a horizontal coiled spring and is brought to rest in a distance of 2.9 m. What is the spring stiffness constant of the spring?

7. ## Chemistry

A 0.250-g sample of a magnesium-aluminum alloy dissolves completely in an excess of HCl (aq) . When the liberated H2 (g) is collected over water at 29 degrees celsius and 752 torr, the volume is found to be 301 mL . The vapor pressure of water at 29

8. ## math

315 divided by 5

9. ## Calculus

an open top box is to be made by cutting congruent squares of side length x from the corners of a 12 by 15 inch sheet of tin and bending up the sides. how large should the squares be? what is the resulting maximum value?

10. ## math

If A and B are independent events, P(A) = 0.35, and P(B) = 0.55, find the probabilities a) P(A intersected B) b) P(A united B)

11. ## physics

While watching ocean waves at the dock of the bay, Otis notices that 8 waves pass beneath him in 30 seconds. He also notices that the crests of successive waves exactly coincide with the posts that are 3 meters apart. What are the period, frequency,

12. ## Physics

Physics Question Please Help? A wire, 20.0 m long, moves at 4.0 m/s perpendicularly through a magnetic field. An EMF of 40V is induced in the wire. What is strength of the magnetic field?

13. ## Chemistry

Of each pair of solids, which one has the higher melting point? a) HCl and KCl b) Cu and Kr. Can you please explain? How do you know the melting point? Is it the type of intermolecular force that they have? thanks!

14. ## Calc

The temperature at any point in the plane is given by the function T(x,y)= 100/(x^2+y^2+1). Find the direction at the point (3,2) in which the temperature does not increase or decrease. Help, please? Thanks!

15. ## maths

jo-jo had two mice, every month the number of mice doubled. in how many months would there be 2048?

16. ## Algebra 1

Question: The height in feet above the ground of an arrow t seconds after it is shot can be modeled by y = -16t(squared) + 63t + 4. Can the arrow pass over a tree that is 68 feet tall? Explain. Completely lost, could anyone help me out?

17. ## calculus

A company manufacturing surfboards has fixed costs of $300 per day and total costs of$5100 per day for a daily output of 20 boards. Assume the total cost per day C(x) is linearly related to the total output per day x. Write an equation for the cost

18. ## Math - Calculus

Show that the equation x^3-15x+c=0 has at most one root in the interval [-2,2].

19. ## Chemistry * FIX

Hydrogen fluoride is produced from the reaction of calicum fluoride with sulfuric acid, which also forms calicum sulfate. 6.00 kg of calicum fluoride are reacted with an excess of sulfuric acid. How much hyrdogen fluoride is formed if the percent yield is

20. ## chemistry

Degree of unsaturation why is it 5? C20H32CIN do i ignore the second C? because i did 21(2)+2=44 44-32+1-1 / 2 = 6 but i get it right with 20(2)+2=42 42-32-1+1 / 2 = 5 do i always ignore extra C's?

21. ## Chemistry

a. what is the pKb of NO2- b. what is the pKa of the hydrazinium ion?

22. ## Physics Craziness

A big olive (m = 0.40 kg) lies at the origin of an xy coordinate system, and a big Brazil nut (M = 1.2 kg) lies at the point (1.0,2.0) m. At t = 0, a force o = (2.0 + 3.0) N begins to act on the olive, and a force n = (-3.0 - 2.0) N begins to act on the

23. ## physics

A 56 kg bungee jumper jumps from a bridge. She is tied to a bungee cord whose unstretched length is 11 m, and falls a total of 38 m. Calculate the spring stiffness constant k of the bungee cord, assuming Hooke's law applies. Calculate the maximum

24. ## chemistry

30.0 mL of 1.50 M NaOH is diluted to 50.0 mL. What is the resulting pH?

25. ## statistics

Five percent of all items sold by a mail-order company are returned by customers for a refund. Find the probability that of two items sold during a given hour by this company both will be returned for a refund

26. ## physics

How long will it take a 1280 W motor to lift a 345 kg piano to a sixth-story window 19.0 m above?

27. ## calculus

The antiderivative of arctan(4t)dt by integration of parts.

28. ## Math

I lost my paper for the Math Riddle Pizazz page 167 about solving systems of equations and I no longer have the problems. (It is the "did you hear about the farmer who gave birdseed to his cows..." page) What are the math problems for it?

29. ## Math - Calculus

Show that the equation x^3-15x+c=0 has at most one root in the interval [-2,2]. Perhaps Rolle's Theorem, Mean Value Theorem, or Intermediate Value Theorem hold clues? ...Other than simply using my TI-84, I have no idea how to accomplish this.

A company decides to investigate the amount of sick leave taken by its employees. A sample of seven employees yields the following number of sick leave taken in the past year 1 1 3 0 1 7 1 a. Find and interpret the range

31. ## Algebra 2

I am completely lost trying to solve this problem. I could really use some help and explanation. x/x+1 + 5/x = 1/x^2+x also how do you write (x-5)(x-5) would it be x^2-5

32. ## math

A triangle has sides of lengths 9 cm, 40 cm, and 41 cm. Which statement is true about this triangle? Not a right triangle?

33. ## physics

An asteroid is moving along a straight line. A force acts along the displacement of the asteroid and slows it down. The asteroid has a mass of 4.9 × 104 kg, and the force causes its speed to change from 7600 to 5400 m/s. (a) What is the work done by the

34. ## organic chem

what are some chemical reasons that might have resulted in a lower yield of a product on a grignard reaction. Something related to grignards being very reactive and since its the limiting reagent, any reaction that destroys it will result in a hit in

35. ## chemistry

find the pK for the following ionization constants, K= 1.8*10^-5 and 1.1*10^.2

36. ## physics

A 1460-kg car is being driven up a 10.0 ° hill. The frictional force is directed opposite to the motion of the car and has a magnitude of 497 N. A force F is applied to the car by the road and propels the car forward. In addition to these two forces, two

37. ## history

What is the government's role in a traditional economy?

38. ## chemistry

What is hybridization and what are the different hybridizations for each molecular geometry?

39. ## physics

A dockworker loading crates on a ship finds that a 25 kg crate, initially at rest on a horizontal surface, requires a 84 N horizontal force to set it in motion. However, after the crate is in motion, a horizontal force of 50 N is required to keep it moving

40. ## physics

An object falling under the pull of gravity is acted upon by a frictional force of air resistance. The magnitude of this force is approximately proportional to the speed of the object, which can be written as f = bv. Assume that b = 14 kg/s and m = 41 kg.

41. ## calculus

find the equation of a quadratic function whose graph is tangent at x=1 to the line whose slope8, tangent at x=-2 to solve the line with slope-4 and tangent to the line y=-8

43. ## physics

A 48.9-g golf ball is driven from the tee with an initial speed of 45.4 m/s and rises to a height of 29.9 m. (a) Neglect air resistance and determine the kinetic energy of the ball at its highest point. (b) What is its speed when it is 5.62 m below its

44. ## physics

A 48.9-g golf ball is driven from the tee with an initial speed of 45.4 m/s and rises to a height of 29.9 m. (a) Neglect air resistance and determine the kinetic energy of the ball at its highest point. (b) What is its speed when it is 5.62 m below its

45. ## physics

The gun, mount, and train car had a total mass of 1.22 106 kg. The gun fired a projectile that was 80.0 cm in diameter and weighed 7502 kg. In the firing illustrated in the figure, the gun has been elevated at è = 18.0° above the horizontal. If the

46. ## physics

Starting at the top of a steep, icy track, a rider jumps onto a sled (known as a skeleton) and proceeds - belly down and head first - to slide down the track. The track has fifteen turns and drops 104 m in elevation from top to bottom. (a) In the absense

47. ## Chemistry

What would the equation be for the reaction between potassium permanganate and cyclohexene. I know it's a oxidation reaction but not sure of the equation.

48. ## Chemistry

Hydrogen Fluoride is produced from the reaction of calicum fluoride are reacted with an excess of sulfuric acid. How much hydrogen fluoride is formed if the percent yield is 93.0%?

49. ## Chemistry

Phosphoric acid reacts with zinc to produce hydrogen gas and zinc phosphate. How many grams of acid are required to produce 5.3 liters of hydrogen at 743mmHg and 27.0 degrees Celsius

50. ## Chem. Percent Yield

Titanium, a strong, lightweight metal used in many applications, is prepared by the reaction of titanium(IV) chloride with molten magnesium metal. 3.45 x 10^7g of titanium(IV) chloride is reacted with 1.13 x 10^7g of magnesium, 7.91 x 10^6g of titanium

51. ## geometry

in the figure, it is given that AB = 21, BC = 14, and AD = 54. find the lenth of CD

52. ## Economics

Are these examples of elastic/inelastic supply products correct? Plane tickets: A plane ticket is an example of inelastic supply. If the price of a ticket changes, the airline cannot quickly increase the supply of seats. It takes a long time to make more

53. ## Chemistry

The ionization constant for benzoic acid is 6.5x10^-5. find the hydrogen ion concentration at equilibrium when the initial concentration is .29M

write the equation of the circle that satisfies each set of conditions. the center of the circle is on the x-axis, its radius is 1, and it passes through the point (square root of 2 over 2, square root of two over 2)

175. ## cal

find the equation of a quadratic function whose graph is tangent at x=1 to the line whose slope8, tangent at x=-2 to solve the line with slope-4 and tangent to the line y=-8 find the equation of the tangent lines at x=1 and x=-2 graph the quadratic

304. ## social studies

How does a person's choice relate to his or her opportunity cost?

305. ## physics

an object travlling at 10m/s accerelates at 10m/s2 for 8seconds.what is the final velocity and how far does it travel during the 8seconds

306. ## algebra

Evaluate each logarithm. 3 to the 2nd power x plus five equals 9x plus 1. I can't seem to type the actual problem, which is why I wrote it out. I hope I wrote the problem right.

307. ## physics

train is approaching the station at a speed of 20m.s sounds a 220 hz horn. What frequency does an observer on the station platform hear

308. ## physics

a box is thrown upwards with a velocity of 8m/s and takes 2seconds to reach its maximum height.how high does it go up

309. ## math

what is the quotient when 3x^3-11x^2+10x-12 is divided by x-3 ?

310. ## sociology-HELP

can i know the example of topic that related in education that can influence society????

311. ## math

i have a three in the ones place,a 5 in the hundreths place.what are three numbers i can get

312. ## behavioral science

earlier this morning I posted a word story and asked for help. I do not want answers to this problem. I just need help in selecting strategies. Perhaps a chess player could help me.

313. ## math

A square is 7 meters on a side. To the nearest tenth of a meter, how long is the diagonal of the square? A: 9.8 B: 9.9 C: 10.0 D: 14.0

314. ## physics

if the angular quantities theta omega and angular acceleration were specified in terms of degrees rather than radians how would the kinematics equations for uniformly accelerated rotational motion have to be altered

315. ## science

How does having more than one lamp in series affect the total voltage in a series circuit? Thanks so much!! :D

316. ## Chemistry

The Chlorination of vinyl chloride, C2H3Cl +Cl2-->C2H3Cl3, is believed to proceed by the following mechanism: Cl2 --(k1)--> 2Cl* Cl* + C2H3Cl --k2--> C2H3Cl2* C2H3Cl2* + Cl2 --k3--> C2H3Cl3 + Cl* C2H3Cl2* + C2H3Cl2* --k4--> stable species Derive the rate

317. ## worldhistory

is the answers to the most important outcome of the mongol peace establishment of a stable,goverment across Eurasia? then i think it is spread of western ideas to the east

318. ## english

prepert speech;A full speech of;The answer to skills shortage in South Africa

319. ## statistics

Five percent of all items sold by a mail-order company are returned by customers for a refund. Find the probability that of two items sold during a given hour by this company both will be returned for a refund

320. ## Math

Hey I need some help in 6th grade geometry. I need to find some random facts about the Metric system and the Coustomary system so that I can create a double bouble map on them. Not only did I need facts on them sepratley I also need facts on what they have

321. ## physices

How would the total (round trip) time in windy weather compare with the total time in calm weather? Please answer this in words, not equations, briefly explaining how you obtained your answer.

322. ## statistics

Five percent of all items sold by a mail-order company are returned by customers for a refund. Find the probability that of two items sold during a given hour by this company both will be returned for a refund

323. ## AP us history

why are the trust protrayed as vultures ?

324. ## physics

a pirate ship fires a 25kg cannonball with a velocity of +100m/s at a very heavy fur trader ship. the ship is at rest. the cannonball bounces off the side of the ship, making a hole. after the collision the cannonball has a velocity of -0.5m/s. assume the

325. ## English

I made a few changes myself. Can you please tell me if everything is possible? 1)The Wildean dandy is on the one hand an aristocrat, who uses his wit to shock the others and on the other hand an individualist who seeks (demands) absolute freedom. 2) He

326. ## chemistry

Put the molecules in order of increasing bond polarity H-F, C-N, AND F-N.