# Robert

Popular questions and responses by Robert-
## Physics - Electromagnetism

A square loop (length along one side = 20 cm) rotates in a constant magnetic field which has a magnitude of 2.0 T. At an instant when the angle between the field and the normal to the plane of the loop is equal to 20 and increasing at the rate of

*asked on August 12, 2012* -
## Statistics

Q1:(a) Make a relative frequency table of the data. Enter your answers to three decimal places. Cell Phone Owned Relative Frequency Android smartphone iPhone smartphone Blackberry smartphone Cell phone not smartphone No cell phone Total (b) Round your

*asked on March 13, 2017* -
## Chemistry

Octane (C8H18) undergoes combustion according to the following thermochemical equation: 2 C8H18(l) + 25 O2(g) ---> 16 CO2(g) + 18 H2O(l) DHo = -11,200 kJ Given : DHfo [CO2(g)] = -393.5 kJ/mol and DHfo[H2O(l)] = -285.8 kJ/mol. Calculate the enthalpy of

*asked on November 25, 2009* -
## Chemistry

An element has three stable isotopes. One has a mass number of 63 and an abundance of 50%. The second has a mass number of 65 and an abundance of 30%. The third has a mass number of 67 and an abundance of 20%. Calculate the relative atomic mass of this

*asked on September 24, 2016* -
## HELP !!! Algebra 2

15. What is the solution of the linear-quadratic system of equations? {y = x^2 + 5x - 3} {y - x = 2}

*asked on November 16, 2012* -
## Physics

A meter stick balances horizontally on a knife-edge at the 50.0 cm mark. With two 5.00 g coins stacked over the 7.0 cm mark, the stick is found to balance at the 41.0 cm mark. What is the mass of the meter stick? The answer is 38g but I don't understand

*asked on December 12, 2010* -
## Physics

A cube made ouk and side 15cm floats in water with 10.5cm of it's depth below the surfaces and with it's side's vertical what is density of oak

*asked on June 20, 2018* -
## Algebra 1

The amount of money in an account may increase due to rising stock prices and decrease due to falling stock prices. Nathan is studying the change in the amount of money in two accounts, A and B, over time. The amount f(x), in dollars, in account A after x

*asked on August 14, 2019* -
## Algebra

Gabriel is making a mixture of compost and soil to use for a special plant. He wants his final mix to be 2 parts compost to 10 parts potting soil. He wants to end up with 12 kilograms of mix.

*asked on October 16, 2019* -
## Physics - Verification

Two long straight parallel wires separated by a distance of 20 cm carry currents of 30 A and 40 A in opposite directions. What is the magnitude of the resulting magnetic field at a point that is 15 cm from the wire carrying the 30-A current and 25 cm from

*asked on August 12, 2012* -
## chemistry

Iron(II) can be oxidized by an acidic K2Cr2O7 solution according to the net ionic equation. Cr2O72− + 6 Fe2+ + 14 H+ 2 Cr3+ + 6 Fe3+ + 7 H2O If it takes 44.0 mL of 0.0250 M K2Cr2O7 to titrate 25.0 mL of a solution containing Fe2+, what is the molar

*asked on March 3, 2011* -
## physics

A bus accelerates from rest at 1.5m/s^2 for 12s. It then travels for 25s after which it slows to a stop with an acceleration of magnitude 1.5m/s^2. (a) Find the total distance the bus travels And its average velocity of the trip.

*asked on September 1, 2013* -
## Chemistry

Calculate the solubility (in g/L) of calcium fluoride in water at 25°C if the Ksp for is 1.5 × 10-10 .

*asked on December 2, 2014* -
## Algebra 2 help :)

Any number in the form of a+-bi , where a and b are real numbers and b not equal 0 is considered a pure imaginary number. TRUE OR FALSE The minimum value is the smallest y-value of a function. T RUE OR FALSE i2 = square root of -1. TRUE OR FALSE Complex

*asked on November 20, 2012* -
## statistics

Smith is a weld inspector at a shipyard. He knows from keeping track of good and substandard welds that for the afternoon shift 5% of all welds done will be substandard. If Smith checks 300 of the 7500 welds completed that shift, what is the probability

*asked on March 18, 2014* -
## Geometry

Line TV bisects

*asked on August 19, 2015* -
## Geometry

Question: If a ray divides an angle into two supplementary angles, then the original angle is a straight angle. True?

*asked on August 20, 2015* -
## Math

The function f given by f(x) = x^3 + 12x – 24 is? Increasing for all x's? Cause that's what I think..

*asked on December 9, 2014* -
## Matg

Juanita told her dad that she won 80% of the card games she played yesterday. If she won 4 games, how many games did she play?

*asked on September 6, 2015* -
## Physics AP

A conical pendulum is formed by attaching a 50 g mass to a 1.2m string. The mass swings around a circle of radius 25cm. A claculate the speed of the mass. B Calculate the acceleration of the mass. C calculate the tension in the string

*asked on December 19, 2013* -
## Chemistry

Is ClO2>- a Bronsted acid, base, or both?

*asked on July 9, 2012* -
## calculus

a fence 8 ft tall stands on level ground and runs parallel to a tall building. if the fence is 1 ft from the building, find the length of the shortest ladder that will extend from the ground over the fence to the wall of the building. (hint #1: if L

*asked on November 17, 2011* -
## Physics - Electromagnetism 2

Two coils, held in fixed positions, have a mutual inductance of 165 µH. What is the peak emf in one coil when the current in the other coil is I(t) = 16.0 sin(1.15 103t), where I is in amperes and t is in seconds? Just a few hints on how to start it off

*asked on August 16, 2012* -
## english4

He will not allow the table to be moved. identify the Verbal in the sentence and type of verbal

*asked on October 3, 2012* -
## Physical Science

If a skydiver has a forward velocity of 40 m/s, what is the forward velocity after one second? What is the downward velocity after one second?

*asked on October 12, 2015* -
## General Chemistry 132

When solid NH4NO3 is dissolved in water at 25celcius, the temp of the solution decreases. What is true about the signs of enthalpy and entropy for this process? I understand entropy is positive, however, i do no understand why enthalpy is also positive.

*asked on May 6, 2015* -
## Physics - Electromagnetism

This is the last question for a final exam preparation sheet and I can't figure out the answer. Any help would be greatly appreciated. Thank you. - One very long wire carries current 10.0 A to the left along the x axis. A second very long wire carries

*asked on July 25, 2012* -
## physics

A cubical piece of heat-shield-tile from the space shuttle measures 0.18 m on a side and has a thermal conductivity of 0.065 J/(s·m·C°). The outer surface of the tile is heated to a temperature of 1050°C, while the inner surface is maintained at a

*asked on May 21, 2012* -
## Physics concept question

A long straight horizontal wire carries a current I = 2.10 A to the left. A positive 1.00 C charge moves to the right at a distance 4.50 m above the wire at constant speed v = 2250 m/s. What are the magnitude and the direction of the magnetic force on the

*asked on March 7, 2011* -
## math

john ordered a new sign for her store. The sign has 4 sides . It also has 2 right angles. 1 acute angle , and 1 obtuse angle . What is the shape of the sign.

*asked on April 10, 2014* -
## physics

If 3000ft/3 of air crossing an evaporator coil and is cooled from 75F to 55F, what would be the volume of air,in ft/3, exiting the evaporator coil?

*asked on February 1, 2013* -
## Math

Go to Table 10-1 which is based on bonds paying 10 percent interest for 20 years. Assume interest rates in the market (yield to maturity) decline from 11 percent to 8 percent: A. What is the bond price at 11%? B. What is the bond price at 8%? C. What would

*asked on January 11, 2010* -
## Chemistry (Biochem)

I'm given two pictures looking down the alpha helices of a coiled coil dimer of alpha-keratin. I'm asked to identify three statements out of the following that are true. My guesses are 2, 3, and 6. 1. Leu-Glu-His-Val-Cys-Lys-Ser is a likely repeat in the

*asked on January 27, 2013* -
## English 11

1. Olaudah Equiano wrote (1 point) a book of letters to his African family. a history of the West Indian slave trade. stories of early slavery in Virginia. the first autobiography by a black man in America. 2. The term “the Middle Passage” refers to (1

*asked on March 12, 2012* -
## Math

The formula h=48t-16t^2 gives the height, h, in feet, of an object projected into the air after t seconds. If an object is propelled upward, at what time(s) will it reach a height of 32 feet above the ground?

*asked on July 27, 2011* -
## Physics

A 40.0kg child is in a swing that is attached to ropes 2.00m long. Find the gravitational potential energy associated with the child relative to the child's lowest position under the following conditions: a) When the ropes are horizontal b) When the ropes

*asked on February 5, 2008* -
## math

Simplify the expression (x to the fourth power times x cubed)squared/x to the 4. a)x b)x to the fifth c)x to the tenth d)x to the 20 I kind of confused. I tried to divide by 4, but i couldn't get anything. I need help?

*asked on January 31, 2008* -
## Chemistry

Dividing 0.32g of sulfur by its density of 2.07g/cm^3 results in an answer with three significant figures? Am I right?

*asked on September 2, 2015* -
## Microeconomics

4a. In the market for hand-made guitars, when the price of guitars is $800, annual revenues are $640,000. When the price falls to $700, annual revenues decline to $630,000. Over this range of guitar prices, is the demand for hand-made guitars elastic,

*asked on October 17, 2012* -
## Physics - Electromagnetism

An inductor in the form of a solenoid contains 440 turns and is 15.8 cm in length. A uniform rate of decrease of current through the inductor of 0.421 A/s induces an emf of 175 µV. What is the radius of the solenoid?

*asked on August 16, 2012* -
## English

1) The following passage is an example of which literary element? "Give back your heart to itself, to the stranger who has loved you all your life, whom you ignored for another, who knows you by heart." a)paradox b)magical realism c)metaphor d)hyperbole*

*asked on January 9, 2012* -
## precalculus

Simplify the Factorial Expression. (3n+1)!*3!/(3n-2)!

*asked on December 5, 2011* -
## math

write 362.63 in words

*asked on September 29, 2009* -
## physics

During an Apollo lunar landing mission, the command module continued to orbit the Moon at an altitude of about 58.6 km. How long did it take to go around the Moon once, in seconds?

*asked on April 2, 2018* -
## Physics

Huck Finn walks at a speed of 0.60 m/s across his raft (that is, he walks perpendicular to the raft’s motion relative to the shore). The raft is traveling down the Mississippi River at a speed of 2.20 m/s relative to the river bank. What is Huck’s

*asked on February 5, 2017* -
## Linear Algebra

The Vector v has a length of 15 and points at an angle of 30 degrees. The Vector u has a length of 17 and points at an angle of 55 degrees. What is u*v? I know to get my answer I need to use this format |u|*|v|*cos(theta) however I am stuck at setting up

*asked on September 6, 2016* -
## chemistry

how many milliliters of 0.250 M KMnO4 are needed to react with 3.55 grams of iron(II)sulfate, FeSO4? the reaction is as follows: 10FeSO4(aq)+2KMnO4(aq)+8H2SO4(aq)¨ 5Fe2(SO4)3(aq)+2MnSO4(aq)+K2SO4(aq)+8H2O(l)

*asked on October 23, 2012* -
## english 4

The two waiters exchanged a look whose meaning was clear to me. what type of clause or phase is used?

*asked on October 3, 2012* -
## English

What are the nouns and verbs in the sentence. Life is full of choices, so I must learn to make good ones.

*asked on September 27, 2012* -
## Biochemistry

Acetylcholinesterase catalyzes the hydrolysis of the neurotransmitter acetylcholine: Acetylcholine + H2O actetate + choline The KM of acetylcholinesterase for its substrate acetylcholine is 9 x 10-5 M. In a reaction mixture containing 5 nanomoles/ml of

*asked on September 22, 2012* -
## Psychology

compare and contrast the strengths and weaknesses of two different approaches to study the following issue: You have developed a new drug that you believe is effective in reducing appetite. As a result of some preliminary research, you have been given a

*asked on August 14, 2011* -
## Physics- Charge in electromagnetic field

An antiproton (which has the same properties as a proton except that its charge is -e) is moving in the combined electric and magnetic fields of the figure: h tt p://post image. org/image/2sh3s3hs4/ What are the magnitude and direction of the antiproton's

*asked on March 7, 2011* -
## Physics

Three uniform meter sticks, each of mass M, are placed on the floor as follows: stick 1 lies along the y axis from y = 1.3 to y = 2.3 m, stick 2 lies along the x axis from x = 0.0 to x = 1 m, stick 3 lies along the x axis from x = 1.0 m to x = 2.0 m. Find

*asked on April 25, 2010* -
## Chemistry 101

Which of the following will not increase the rate of a reaction? a. using a catalyst b.increasing the temperature c. decreasing the concentration of a reactant d. finding a shorter path for the reaction to take place e. increasing the kinetic energy

*asked on October 25, 2009* -
## math

Solve each equation and leave the answer in simplest radical form. x squared+6x-9=0 n squared-2n+2=5 3y squared-4y-2=0 I never learned how to do this. Can you help me?

*asked on December 10, 2007* -
## Math

A helicopter drops a box of supplies after a disaster. The function represents the height y (in feet) of the box t seconds after it is dropped. After how many seconds does the box hit the ground? y=100-16t^2

*asked on April 30, 2018* -
## pre calc

The number N of bacteria in a culture at time t (in hours) grows exponentially according to the function N(t) = 1000e^0.01t When will the number of bacteria reach 1700? I though you would do 1700=1,000^e0.01t and solve for t but i keep getting the wrong

*asked on March 11, 2017* -
## Calculus

Two points P and Q are connected by a straight road of length d. At time t = 0, a car starts driving from P to Q at a constant speed c. At t = 0, a bee starts flying from Q toward the car at a constant speed b > c, and takes a zig-zagging path, reversing

*asked on September 6, 2014* -
## algerbra

Consider the following system of equations. y = 4x - 4 y - 4x = 3 What can you conclude about the system of equations?

*asked on September 1, 2014* -
## Chemistry

1.) A 3.000gram sample of a hydrate compound containing Co, C2O4, and H2O was combusted to give 1.316g of Co3O4. What is the percentage of Cobalt in the oxide? 3.) 2.000 grams of a sample containing Co, C2O4, and H2O showed there to be 0.9621g of oxalate

*asked on March 3, 2013* -
## Chemistry

An aqueous solution of ethanol is 14.1M C2H5OH. The density of the solution is 0.853g/mL. What is molality of ethanol in the solution? What is mass % of ethanol in solution? I got the molality which is -21.7 ethanol, but I can't figure out how to get the

*asked on January 14, 2013* -
## chemistry

in an experiment, 2.50g of salicylic acid is reacted with 10.31g of methanol. the yield of methyl salicylate, C8H8O3, is 1.27g. what is the percentage yield?

*asked on October 13, 2012* -
## chemistry

if a reaction vessel contains 11.5g NH3, 12.0g O2, and 10.5g CH4, what is the maximum mass in grams of hydrogen cyanide that could be made?

*asked on October 13, 2012* -
## chemistry

copper metal reacts with nitric acid. assume that the reaction is 3Cu(s) + 8HNO3(aq) ——> 3Cu(NO3)2(aq) + 2NO(g) + 4H2O(l). if 5.58 grams of Cu(NO3)2 is obtained, how many grams of nitrogen monoxide would have formed

*asked on October 12, 2012* -
## english4

what type of clause or phrase is used in the sentence: we hit a snag while rowing to shore

*asked on October 3, 2012* -
## World geography

This very southern city in Africa is in an area of moderate rainfall

*asked on December 6, 2011* -
## Chemistry

Ethanol, C2H5OH or C2H6O, is mixed with gasoline and sold as gasohol. Given the following thermo-chemical reaction, calculate the kilograms (kg) of CO2 produced when enough ethanol is combusted to provide (or give off) 369 kJ of heat: C2H5OH (l) + 3 O2 (g)

*asked on July 12, 2011* -
## SCIENCE

DEFINE AND GIVE EXAMPLES 1. Sexual reproduction 2. asexual reproduction

*asked on April 27, 2011* -
## SQL

1- A SQL statement is needed to create a stored procedure that has one input parameter of data type int. The stored proc selects the supplierId field and the total, or sum, of all Count field values for each group of supplierId fields from the Part table.

*asked on April 15, 2011* -
## Physics

a 2 kg block slides down a frictionless incline from point A to point B. A force(magnitude P=3N) acts on the block between A and B, as shown. Points A and B are 2 m apart. If the kinetic energy of the block at A is 10 J, and the work done by gravity is

*asked on March 24, 2011* -
## chemistry

how many grams of manganese (4) oxide are needed to make 5.6 liters of a 2.1 solution

*asked on March 10, 2011* -
## math

North Pole Cruise Lines issued preferred stock many years ago. It carries a fixed dividend of $6 per share. With the passage of time, yields have soared from the original 6 percent to 14 percent (yield is the same as required rate of return). A. What was

*asked on January 11, 2010* -
## science

the ? describes the steps you use during an experiment?

*asked on August 11, 2009* -
## calculus

The illumination of an object by a light source is directly proportional to the strength of the source and inversely proportional to the square of the distance from the source. If two light sources, one three times as strong as the other, are placed 11 ft

*asked on June 30, 2009* -
## chemistry

Ibuprofen, the active ingredient in Advil, is made up of carbon, hydrogen, and oxygen atoms. When a sample of ibuprofen, weighing 5.000 g, burns in oxygen, 13.86g of CO2 and 3.926 g of water are obtained. What is the simplest formula of ibuprofen? I need

*asked on October 4, 2008* -
## math

How do you find the area of something?

*asked on January 14, 2008* -
## Chemistry

True or false? All enzymes are specific to a single substrate chemical. That is, an enzyme will catalyze reactions of one molecule only.

*asked on October 24, 2007* -
## Calc Help

A manufacturer's revuenve in dollars is given by R(x)=1500x-0.02x^2 where x is number of units sold. Find the marginal revenue function. Use the derivative to estimate the revenue gained from selling the 35th unit. The marginal revenue function is the

*asked on February 16, 2007* -
## Pre Calculas

Complete the identity sin theta / cos theta + cos theta / sin theta = ? Do you mean (sin theta/cos theta) + (cos theta/sin theta) ? That would equal tan x + cot x = tan x + (1/tan x) = (tan^2 x + 1)/ tan x I don't see any way to further simplify it.

*asked on June 10, 2006* -
## Math

A biologist wants to know the width w of a river so that instruments for studying the pollutants in the water can be set properly. From point A, the biologist walks downstream 100 feet and sights to point C. From the sighting, it is determined that theta =

*asked on April 8, 2020* -
## Organic Chemistry

Procedure: 1) Accurately weigh approximately 0.40 g of Dimethyl maleate into a 50 mL round bottom flask that possesses a ground glass joint, and record the weight. 2) Dissolve the Dimethyl maleate in 10 mL of methanol, and add approximately 5 drops of

*asked on October 15, 2017* -
## Organic Chemistry

Procedure: 1) Accurately weigh approximately 0.40 g of Dimethyl maleate into a 50 mL round bottom flask that possesses a ground glass joint, and record the weight. 2) Dissolve the Dimethyl maleate in 10 mL of methanol, and add approximately 5 drops of 10%

*asked on October 15, 2017* -
## Math

Find the vertex focus directrix and axis of symmetry of each parabola y²–8x–6y–3=0

*asked on May 19, 2017* -
## pre calc

The population of a colony of mosquitoes grows exponentially according to the function P(t) = P0ekt 1. If there are 1,000 mosquitoes initially and there are 1800 after 1 day, what is the size of the colony after 3 days? 2. How long will it take the colony

*asked on March 10, 2017* -
## Physics

After today’s test, you are going to meet some friends at Disney World. The total distance to Disney World is 68 miles. If you make it there in 72 minutes, what is your average velocity in miles per hour?

*asked on February 5, 2017* -
## math

i need ratios of 5/6

*asked on December 6, 2016* -
## Math

An 8.5 centimeter green bean pod contains peas that average 0.45 centimeter in diameter. How many peas are in the pod

*asked on October 18, 2016* -
## Communication for Business

Please could you help me with a good attention getter for a presentation on how interviews were done

*asked on April 16, 2016* -
## Math

Gina has 4 red ribbons, 6 times as many blue ribbons as green ribbons, and 1/4 as many green ribbons as red ribbons. How many ribbons does she have in all?

*asked on April 5, 2016* -
## physics

What is the mass which causes a spring of k = 100 N/m to stretch by 10 cm?

*asked on February 15, 2016* -
## navarro college biology

During the sequencing of dna into a protein, what is the first step?

*asked on June 13, 2015* -
## math

2 line segments intersect to form an angle that has a measure pf 50.7 degrees. What is the measure in degrees of an angle that is supplementary to this angle. I don't understand what this question is asking me. Can someone explain it to me?

*asked on April 9, 2015* -
## physics

car doing 60 mph and skids for 52.3 meters what is the speed at end of skid co/friction is 0.693 urgent help please

*asked on November 3, 2014* -
## math

Identify the solution(s) of the system of equations, if any. x + 3y = 7 6x - 9y = 6

*asked on September 8, 2014* -
## Management

When a manager performs symbolic duties as the head of an organization, that manager is called a

*asked on July 28, 2014* -
## math

sweets are shared equally among 20 children at a party. if there were 1 more sweet and 1 more child, each child would get 1 sweet less. how sweets were shared at the party? thats how the question ends.

*asked on April 23, 2014* -
## Physics -- URGENT

Estimate the force a person must exert on a string attached to a 0.200 kg ball to make the ball revolve in a circle when the length of the string is 0.600 m. The ball makes 1.40 revolutions per second. Do not ignore the weight of the ball. In particular,

*asked on January 8, 2014* -
## Math

An article in the local paper states that 30% of the students at Oak Grove Middle School earned a place on the Silver Honor Roll. If there are 920 students at Oak Grove, how many are on the Silver Honor Roll? USE A PERCENT RULER TO HELP YOU DECIDE. SHOW

*asked on October 30, 2013* -
## algebra!!!! please help me!!!!

The smallest possible positive value of 1−[(1/w)+(1/x)+(1/y)+(1/z)] where w, x, y, z are odd positive integers, has the form a/b, where a,b are coprime positive integers. Find a+b.

*asked on June 14, 2013* -
## Chemistry

59.0 mL of a 1.80 M solution is diluted to a total volume of 268 mL. A 134-mL portion of that solution is diluted by adding 171 mL of water. What is the final concentration? Assume the volumes are additive.

*asked on March 19, 2013*