Friday

October 28, 2016
Total # Posts: 97

**Probability**

What is the probability of passing a 10-item multiple choice quiz, if there are 4 choices, A to D for every question, and if the passing mark is 8/10, assuming that you guessed the answers to all the questions?

*November 5, 2014*

**science**

What is the otter's acceleration if it increases its speed 3 m/s each second for 4 seconds

*November 15, 2013*

**history: please help for a survey**

what is your reaction on the first and second opium war?

*September 16, 2011*

**math**

Which is steeper, y = 4x+ 5 or y = - 5x - 2 ?

*August 17, 2011*

**Algebra 2**

Graph x^2+y^2=16

*June 2, 2011*

**Physics**

In principle, anytime someone jumps up, the earth moves in the opposite direction. To see why we are unaware of this motion, calculate the recoil speed of the earth when a 65.0 kg person jumps upward at a speed of 1.70 m/s. v=?

*March 8, 2011*

**physics**

A. What is the mass of a book that weighs 3.20 N in the laboratory? B.In the same lab, what is the weight of a dog whose mass is 14.0 kg?

*February 2, 2011*

**physics**

A box rests on a frozen pond, which serves as a frictionless horizontal surface. If a fisherman applies a horizontal force with magnitude 44.0 N to the box and produces an acceleration of magnitude 2.80 m/s^{2}, what is the mass of the box?

*February 2, 2011*

**PHYSICS**

A warehouse worker pushes a crate along the floor, as shown in the figure , by a force of 10.0 N that points downward at an angle of 45.0 degree below the horizontal. A. Find the horizontal component of the push. B.Find the vertical component of the push.

*February 2, 2011*

**physics multiple choice**

Far from any gravity, an astronaut accidentally releases a metal wrench inside a spaceship that is traveling at a constant velocity of 250 km/s away from earth in outer space. What will be the subsequent behavior of that wrench as observed by the astronaut? A. It will fall to ...

*February 2, 2011*

**physics multiple choice**

A worker pushes horizontally on a 2000 N refrigerator on a kitchen floor with a force of 28.0 N. A. If the refrigerator moves forward, this person feels it pushing back with less than 28.0 N. B. The person always feels a 28.0 N push from the refrigerator. C. The person feels a...

*February 2, 2011*

**physics multiple choice**

A person pushes horizontally with constant force P on a 230 N box resting on a frictionless horizontal floor. Which of the following statements about this box is correct? A.The box will accelerate no matter how small P is. B. The box will not accelerate unless P > 230 N. C...

*February 2, 2011*

**physics multiple choice**

A 3.00 lb. physics book rests on an ordinary scale that is placed on a horizontal table. The reaction force to the downward 3.00 lb force on the book is A. an upward 3.00 lb force on the scale due to the table. B.an upward 3.00 lb force on the book due to the scale. C.an ...

*February 2, 2011*

**physics multiple choice**

A force F is required to push a crate along a rough horizontal floor at a constant speed V with friction present. What force is needed to push this crate along the same floor at a constant speed 3V if friction is the same as before? A. A constant force 3F is needed. B. A force...

*February 2, 2011*

**physics**

A Ferris wheel with radius 14.0 m is turning about a horizontal axis through its center, as shown in the figure below. The linear speed of a passenger on the rim is constant and equal to 6.00 m/s. A.What is the magnitude of the passenger's acceleration as she passes ...

*February 2, 2011*

**physics**

You swing a 2.00 kg stone in a circle, using the full length of a thin 80.0 cm rope. At what speed should you swing it so its acceleration will be 9.8 m/s^2?

*February 2, 2011*

**physics**

A daring 510 { N} swimmer dives off a cliff with a running horizontal leap, as shown in the figure below. What must her minimum speed be just as she leaves the top of the cliff so that she will miss the ledge at the bottom, which is 1.75 {m} wide and 9.00 {m} below the top of ...

*January 26, 2011*

**physics**

In February 2004, Austrian physicists measured two events (having to do with the behavior of electrons) separated by the shortest time interval ever measured, 100 attoseconds. How far would light travel in this time interval? (1 attosecond = 10^{-18} second)

*January 26, 2011*

**physics**

Astronauts on our moon must function with an acceleration due to gravity of 0.170g . A. If an astronaut can throw a certain wrench 14.0 { m} vertically upward on earth, how high could he throw it on our moon if he gives it the same starting speed in both places? B. How much ...

*January 26, 2011*

**physics**

A brick is released with no initial speed from the roof of a building and strikes the ground in 1.50 {s}, encountering no appreciable air drag. A. How tall, in meters, is the building? B.How fast is the brick moving just before it reaches the ground?

*January 26, 2011*

**physics**

The Pacific Crest Trail runs from the Mexican border to the Canadian border through California, Oregon, and Washington,covering 2650 miles of trail, but only about 1000 straight-line miles. B).If you hike this trail in 14.0 weeks, from Mexico to Canada,find your average ...

*January 26, 2011*

**physics**

You shoot a bullet at a tasty apple high up in a tree some feet in front of you, hoping to knock it loose so you can catch it and eat it. In order to hit this apple, you should aim A. directly at it. B. above it. C. below it.

*January 25, 2011*

**physics**

A rock dropped from a small bridge encounters no air resistance and hits the pond below 1.0 s later. If it had been thrown horizontally with a speed of 10 m/s, then it would have hit the water A. more than 1.0 {s} later, since it has a greater distance to travel. B. 1.0 {s} ...

*January 25, 2011*

**physics**

The "reaction time" of the average automobile driver is about 0.700 s. (The reaction time is the interval between the perception of a signal to stop and the application of the brakes.) If an automobile can slow down with an acceleration of 12.0 ft/s^{2}, compute the ...

*January 20, 2011*

**chemistry**

What is the lewis dot structure of IF2-?

*November 6, 2010*

**chemistry**

What is the lewis dot structure for IBr4-?

*November 6, 2010*

**chemistry**

Lewis dot structure of IF4+

*November 6, 2010*

**chemistry**

A molecule with the formula AB(3) has a trigonal planar geometry. How many electron groups are on the central atom (A)?

*November 6, 2010*

**chemistry**

Sulfur forms the following compounds with chlorine. Identify thetype of hybridization for the central sulfur atom in each compound. SCl2,SCl6,SCl4 a. sp b. sp2 c. sp3 d. sp3d e. sp3d2

*November 6, 2010*

**chemistry**

95.0 mL of H_2O is initially at room temperature (22 degree C). A chilled steel rod at 2 degree C is placed in the water. If the final temperature of the system is 21.3 degree C, what is the mass of the steel bar?

*October 18, 2010*

**chemistry**

How much heat is required to warm 1.30 L of water from 30.0 degrees C to 100.0 degrees C? (Assume a density of 1.0 g/mL for the water.)

*October 18, 2010*

**chemistry**

What mass of natural gas CH_4 must you burn to emit 259 kJ of heat?

*October 18, 2010*

**chemistry**

How much heat is required to warm 1.60 L of water from 26.0 degree C to 100.0 degree C? (Assume a density of {1.0 g/ml for the water.)

*October 18, 2010*

**chemistry**

Calculate the empirical formula for each of the following natural flavors based on their elemental mass percent composition. nitroglycerin (used medically as a vasodilator to treat heart conditions): C 15.87% H 2.22% N 18.50% O 63.41%. Express your answer as a chemical formula.

*September 20, 2010*

**chemistry**

Calculate the empirical formula for each of the following natural flavors based on their elemental mass percent composition. vanillin (responsible for the taste and smell of vanilla): C 63.15% H 5.30% O 31.55%.

*September 20, 2010*

**chemistry**

A sugar crystal contains approximately 1.7×10^17 sucrose (C12H22O11) molecules What is its mass in mg?

*September 20, 2010*

**chemistry**

Calculate the mass in g of each of the following. a. 2.3×10^22 H2O molecules b. 6.16×10^20 SO3 molecules c. 5.0×1025 O3 molecules d. 9.82×1019 CCl2F2 molecules

*September 19, 2010*

**chemistry**

A sugar crystal contains approximately 1.7×10^17 sucrose (C12H22O11) molecules What is its mass in mg?

*September 19, 2010*

**chemistry**

Calculate the empirical formula for each of the following natural flavors based on their elemental mass percent composition. vanillin (responsible for the taste and smell of vanilla): C 63.15% H 5.30% O 31.55%.

*September 19, 2010*

**chemistry**

Calculate the empirical formula for each of the following natural flavors based on their elemental mass percent composition. nitroglycerin (used medically as a vasodilator to treat heart conditions): C 15.87% H 2.22% N 18.50% O 63.41%. Express your answer as a chemical formula.

*September 19, 2010*

**chemistry**

Calculate the mass percent composition of carbon in the following carbon compound. C_8H_13O_5N I got 0.4729 as an answer but it's wrong. Please help me.

*September 11, 2010*

**chemistry**

Calculate the mass percent composition of carbon in each the following carbon compounds. a) C_4H_10 b) C_6H_10 c) CCl_2F_2 d) C_8H_13O_5N

*September 11, 2010*

**chemistry**

What is the name of the following organic compound? CH_3CH_2CCCH_2CH_2CH_3

*September 11, 2010*

**chemistry**

Calculate the mass, in grams, of each of the following. a) 1.2×10^23 gold atoms b) 2.78×10^22 helium atoms c) 2.0×10^23 lead atoms d) 7.6×10^21 uranium atoms

*September 10, 2010*

**chemistry**

What is the mass, in grams, of each of the following? a) 2.4×10−3 mol Sb b) 3.59×10−2 mol Ba c) 43.6 mol Xe d) 1.4 mol W

*September 10, 2010*

**chemistry**

A 8.13 g sample of HCN is found to contain 0.301 g of H and 4.22 g of N. Find the mass of carbon in a sample of HCN with a mass of 3.39 g.

*September 10, 2010*

**chemistry**

Naturally occurring iodine has an atomic mass of 126.9045. A 12.3849 -g sample of iodine is accidentally contaminated with 1.00070 g of ^129 I, a synthetic radioisotope of iodine used in the treatment of certain diseases of the thyroid gland. The mass of ^129 I is 128.9050amu...

*September 8, 2010*

**chemistry**

What is the molar concentration of 2000. mL of aqueous solution containing 125 g of glucose, C6 H12O6? Molar mass 180.15 g/mol. Report your answer to three significant figures.

*September 5, 2010*

**chemistry**

2.633 ounces of aluminum were added to a graduated cylinder containing 16.71 mL of water. What is the new water level after adding the aluminum? The density of aluminum is 2.702 g/ mL.

*September 5, 2010*

**chemistry**

A tank has a pressure of 20.3 atm at a temperature of 22.6 oC. After heating, the temperature rises to 52.7 oC. What is the new pressure?

*September 5, 2010*

**chemistry**

A gas with a temperature of 31.3 oC and a volume of 109.2 L is compressed to 11.7 L. What will be the new temperature? Report your answer to one decimal place.

*September 5, 2010*

**chemistry**

What is the molar concentration of 2000. mL of aqueous solution containing 125 g of glucose, C6 H12O6? Molar mass 180.15 g/mol. Report your answer to three significant figures.

*September 5, 2010*

**chemistry**

What is the oxidation number of sulfur in SO4-2?

*September 5, 2010*

**chemistry**

Phosphoric acid reacts with magnesium carbonate to produce? When you predict the products and write a balanced equation the coefficient of phosphoric acid is a.1 b.2 c.3 d.6 e.4

*September 5, 2010*

**math**

You find 30 coins in your drawer. 20 % of the coins are nickels. How much money you have in nickels?

*September 5, 2010*

**chemistry**

Ba

*September 5, 2010*

**chemistry**

A certain element forms an ion with 54 electrons and a charge of +2. Identify the element.

*September 5, 2010*

**chemistry**

The proton has a radius of approximately 1.0 times 10^{ - 13} cm and a mass of 1.7 times 10^{ - 24} g. Determine the density of a proton. For a sphere V = (4/3)times pi r^3.

*September 5, 2010*

**chemistry**

While in Europe, if you drive 125 km per day, how much money would you spend on gas in one week if gas costs 1.10 euros per liter and your car's gas mileage is 39.0 mi/gal? Assume that 1euro= 1.26; dollars.

*September 4, 2010*

**chemistry**

The speed of light is 3.00 times 10^8~m/s. How fast is this in miles per hour (miles/h)?

*September 4, 2010*

**chemistry**

There are exactly 60 seconds in a minute, there are exactly 60 minutes in an hour, there are exactly 24 hours in a mean solar day, and there are 365.24 solar days in a solar year. Find the number of seconds in a solar year.

*September 4, 2010*

**chemistry**

Total U.S. farmland occupies 954 million acres. How many square miles is this? (1 acre = 43,560 ft^2 , 1 mile= 5280 ft ).

*September 3, 2010*

**chemistry**

There are exactly 60 seconds in a minute, there are exactly 60 minutes in an hour, there are exactly 24 hours in a mean solar day, and there are 365.24 solar days in a solar year. Find the number of seconds in a solar year.

*September 3, 2010*

**Chemistry**

7.87 g/ml

*August 27, 2010*

**Chemistry**

The density of iron is 7.87 . What is the mass of a (variable l)* 4.00cm * 1.00 cm block of iron?

*August 27, 2010*

**chemistry**

The density of iron is 7.87 . What is the mass of a l* 4.00cm * 1.00 cm block of iron?

*August 27, 2010*

**chemistry**

is this correct .737g/mL * 1mL/0.000264...gal*12.9gal=35,989,045.5 grams

*August 27, 2010*

**chemistry**

A particular brand of gasoline has a density of 0.737 g/mL at 25 Celcius. How many grams of this gasoline would fill a 12.9 gal tank?

*August 27, 2010*

**chemistry**

A block of metal has a width of 3.2 cm, a length of 17.1 cm, and height of 3.7 cm. Its mass is 1.3 kg. Calculate the density of the metal.

*August 27, 2010*

**pharmacy**

how much interest will mary owe if she borrows $2000 at a rate of 6% for 2 years?

*August 15, 2010*

**pharmacy**

A CERTAIN MIXTURE CALLS FOR 6MG OF AMOXYCILLIN TO 15 LITERS OF WATER.? HOW MANY LITERS OF WATER WOULD YOU NEED FOR 12MG OF AMOXYCILLIN?

*August 15, 2010*

**calculus**

A container with square base, vertical sides, and open top is to be made from 2700 square feet of material. Find the dimensions (length × width × heigth) of the container with greatest volume.

*August 1, 2010*

**calculus**

Verify that the hypotheses of the Mean-Value Theorem are satisfied on the given interval, and find all values of c in that interval that satisfy the conclusion of the theorem. f(x)=x^2-3x; [-2,6]

*August 1, 2010*

**calculus**

Verify that the hypotheses of Rolle’s Theorem are satisfied for f(x)=6cosx on the interval [9pi/2,11pi/2] and find all values of c in this interval that satisfy the conclusion of the theorem.

*August 1, 2010*

**calculus**

A fertilizer producer finds that it can sell its product at a price of p=5000-1.0x dollars per unit when it produces x units of fertilizer. The total production cost (in dollars) for units is c(x)=150000+1250x+0.25x^2 If the production capacity of the firm is at most 1000 ...

*July 31, 2010*

**calculus**

An open box is to be made from a 21 ft by 56 ft rectangular piece of sheet metal by cutting out squares of equal size from the four corners and bending up the sides. Find the maximum volume that the box can have.

*July 31, 2010*

**calculus**

A rectangle is to be inscribed in a right triangle having sides of length 36 in, 48 in, and 60 in. Find the dimensions of the rectangle with greatest area assuming the rectangle is positioned as in the accompanying figure. right triangle: hypotenuse- 60in base-36in height-48in

*July 31, 2010*

**Calculus**

estimate the absolute maximum and minimum values of f if any, on the stated interval, and then use calculus methods to find the exact values: f(x)=10ln(x^2+1)-8x; [0,3]

*July 31, 2010*

**Calculus**

Find the absolute maximum and minimum values of f on the given closed interval, and state where those values occur. f(x)=5x-10sinx ; [-pi/4,pi/2]

*July 31, 2010*

**calculus **

Evaluate the Integral 1. integral of (x^9+7x^6-1)/x^8 dx 2. integral of x^(1/3)*(42-x)^2 dx 3. integral of 9x+5/7x^3 dx

*July 25, 2010*

**Calculus**

it is all one equation, it's (2-x)to the power of 3tan[(pi/2)x]

*July 25, 2010*

**Calculus**

Find the limit limit as x approaches 1 of (2-x)^3tan[(pi/2)x]

*July 25, 2010*

**calculus**

Find the limit limit as x approaches 1 of (2-x)^3tan[(pi/2)x]

*July 25, 2010*

**Calculus**

Evaluate the Integral 1. integral of (x^9+7x^6-1)/x^8 dx 2. integral of x^(1/3)*(42-x)^2 dx 3. integral of 9x+5/7x^3 dx

*July 25, 2010*

**Calculus**

Find dy/dx y=e^(4xtan2x)

*July 21, 2010*

**Biology**

How do sperm and eggs differ in size? (consider size and the quatity of each gamete). Explain possible reasons for these differences.

*July 19, 2010*

**Biology**

How do the sizes of the oocytes differ as they move from the follicular stage towards the mature graafian follicle?

*July 19, 2010*

**Biology**

1. Why are cells from a blastula used to examine mitosis? 2. How fast do you think cells divide when an embryo is developing compared to the normal growth of an animal?

*July 19, 2010*

**Biology**

Given colchicine's properties, could this compound be used to treat cancer?

*July 19, 2010*

**devry**

Downloading resources from the Web is beginning to be fairly common. What do you think the legal issues are when doing this? Should people expect to give up property rights to material they have created when they post it on the Web? Why or why not?

*May 19, 2010*

**english**

what idea is the fundamental to the contemporary concept of criminal justice?

*September 10, 2009*

**english**

and infamous is reowned

*September 9, 2009*

**english**

maybe purge is stain pollute

*September 9, 2009*

**english**

yes i have all the definitions my choices of antonyms are stain,pollute abhor renowned boasting

*September 9, 2009*

**english**

choose an antonym of these words relish purge cowering infamous

*September 9, 2009*

**Physics**

How do you turn 30 degrees to radians?

*December 1, 2008*

**Spelling/Analogy**

rotund is to shape as a.tiny is to size b.wide is to length

*January 30, 2008*

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