# erin

Popular questions and responses by erin-
## physics

The outstretched hands and arms of a figure skater preparing for a spin can be considered a slender rod pivoting about an axis through its center. When the skater's hands and arms are brought in and wrapped around his body to execute the spin, the hands

*asked on April 12, 2008* -
## physics

As you hurry to catch your flight at the airport, you encounter a moving walkway that is 85m long and has a speed of 2.2 m/s relative to the ground. If it takes you 68s to cover 85m when walking on the ground, how long will it take you to cover the same

*asked on October 2, 2011* -
## statistics

the probability that a football game will go into overtime is 17%. In 240 randomly selected football games, what is the mean and the standard deviation of the number that went into overtime

*asked on June 23, 2013* -
## physics

A solid uniform marble and a block of ice, each with the same mass, start from rest at the same height above the bottom of a hill and move down it. The marble rolls without slipping, but the ice slides without friction. Find the speed of each of these

*asked on April 6, 2008* -
## chemistry

Calculate the amount of heat required to completely sublime 24.0 g of solid dry ice CO_2 at its sublimation temperature. The heat of sublimation for carbon dioxide is 32.3 kJ/mol.

*asked on September 7, 2008* -
## calculus

Find the dimensions of the rectangle with area 225 square inches that has a minimum perimeter, and then find the minimum perimeter.

*asked on March 29, 2020* -
## History

What impact did industrialization have on imperialism? a. Developing European nations needed to conquer foreign territory to compete with industrialized nations b. An increase in production lead to the need for new land to build factories in foreign

*asked on February 25, 2019* -
## chemistry

How do you do the hybridization of CBr4?

*asked on March 5, 2012* -
## Physics

A child pedals a tricycle, giving the driving wheel an angular speed of w=.875 rev/s. If the radius of the wheel is r=0.260 m, what is the child's linear speed, v?

*asked on June 30, 2019* -
## Languege arts

1. Which is the BEST summary of "LAFFF"? (1 point) Angela used a time machine to win a writing contest. Peter and Angela invented a time machine. Peter used a time machine to travel to the future. 2. The author describes Peter's Halloween costume in order

*asked on February 7, 2013* -
## Physics

A skateboarder at a skate park rides along the path. If the speed of the skateboarder at point A is v=1.4 m/s what is her speed at point B? Point A = 2.7 m & Point B=1.0 m

*asked on June 30, 2019* -
## Trig

The seats of a Ferris wheel are 40 feet from the wheel's center. When you get on the ride, your seat is 6 feet above the ground. How far above the ground are you after rotating through an angle of 17pi/4?

*asked on June 2, 2018* -
## math

A hot air balloon descends at a rate of 320 feet per minute for 3 minutes. Whats the balloons total change in altitude?

*asked on May 17, 2013* -
## Math

How do you set this up? Solve the system using substitution: A boat travels 18 miles downstream in 1.5 hrs. It then takes the boat 3 hrs. to travel upstream the same distance. Find the speed of the boat in still water and the speed of the current. Thanks

*asked on December 6, 2012* -
## Chemistry: help please

What is the millimolar solubility of oxygen gas,O2, in water at 20 degree celsius, if the pressure of oxygen is 1.00atm?

*asked on February 1, 2009* -
## Social Studies

Hi Jiskha!! I have been researching the Civil war and wanted to know it you can add to this. No this is not my work it is essays and summary's i found on the computer, this is what I found: Summary of the Civil War: Fought 1861-1865, the American Civil War

*asked on November 10, 2010* -
## English

Read the following passage "I don't know anything," he said, "except that I'm beginning to be sorry we bought that room for the children. If children are neurotic at all, a room like that -" "It's supposed to help them work off their neuroses in a

*asked on May 2, 2016* -
## Algebra 2

The formula A = 180(n-2)/n relates to the measure A of an interior angle of a regular polygon to the number of sides n. If an interior angle measures 120 degrees, find the number of sides A)5 B)6 C)8 D)10 I have NO clue on how to do this pls help. Make A

*asked on July 15, 2007* -
## physics

A tetherball leans against the smooth, frictionless post to which it is attached.The string is attached to the ball such that a line along the string passes through the center of the ball. The string is 1.20m long and the ball has a radius of 0.120mwith

*asked on February 27, 2008* -
## Elementary Statistics

1) Construct a confidence interval of the population proportion at the given level of confidence. x=60,n=300, 99% confidence. The 99% confidence interval is (_,_) 2) A researcher wishes to estimate the proportion of adults who have high-speed internet

*asked on June 6, 2012* -
## physics

An Astronaut on the Moon drops a rock straight downward from a height of 1.25 meters. If the acceleration of gravity on the Moon is 1.62 meters per second squared, what is the speed of the rock just before it lands?

*asked on October 1, 2011* -
## college algebra

The height of an object thrown upward with an initial velocity of 96 feet per second is given by the formula h = -16t2 + 96t, where t is the time in seconds. How long will it take the object to reach a height of 144 feet?

*asked on September 22, 2010* -
## physics

A motorcycle stunt rider must jump a 100m wide canyon given a 20° ramp positioned on either side. What minimum speed is required so the rider will clear the canyon?

*asked on October 17, 2010* -
## Physics

Liz rushes down onto a subway platform to find her train already departing. She stops and watches the cars go by. Each car is 8.60 m long. The first moves past her in 1.75 s and the second in 1.17 s. Find the constant acceleration of the train. I know how

*asked on October 10, 2009* -
## Physics

The command module orbited at an altitude of 110 km above the lunar surface. How much time did it take for the command module to complete one orbit?

*asked on July 20, 2019* -
## Math

The Coffee Counter charges $11.00 per pound for Kenyan French Roast coffee and $15.00 per pound for Sumatran coffee. How much of each type should be used to make aa 24 pound blend that sells for $13.00 per pound?

*asked on January 22, 2018* -
## Algebra

You operate a gaming Web site, where users must pay a small fee to log on. When you charged $3 the demand was 520 log-ons per month. When you lowered the price to $2.50, the demand increased to 780 log-ons per month. (a) Construct a linear demand function

*asked on February 21, 2012* -
## college algebra

Use point-slope form to write the equation of the line with the given properties. Write the equation in standard form. m is undefined passing through P(-7, -7)

*asked on October 13, 2010* -
## physics

It is reasonable to assume that the bulk modulus of blood is about the same as that of water (2.20 GPa). As one goes deeper and deeper in the ocean, the pressure increases by 1.0*10^4 Pa for every meter below the surface. If a diver goes down 33.0 m (a bit

*asked on April 13, 2008* -
## Chemistry

Calculate the wavelengths: -A muon (a sub particle with the mass of 1.884 X 10^-25g) traveling at 320.0 m/s -an electron (me=9.10939 x 10^-28g) moving at 3.85 x 10^6 m/s -An 83.0kg athlete running a "4 minute mile" (i.e. 400min/mile)

*asked on March 31, 2019* -
## Math

A corporation has 7 members on its board of directors. How many different ways can it elect a president, vice president,secretary, and treasurer?

*asked on July 29, 2013* -
## Trig

Two ships leave a harbor at the same time. One ship travels on a bearing S11 degrees W at 12 mph. The second ship travels on a bearing N75 degrees E at 9 mph. How far apart will the ships be after 3 hours?

*asked on June 29, 2018* -
## Chemistry

A pediatrician prescribes the antibiotic amoxicillin to treat a child suffering from an ear infection. The prescribed dose is to be 72.1 mg of drug per kilogram patient body mass per day. The drug is to be administered twice each day in the form of a

*asked on September 19, 2017* -
## Physics

A man of mass 75 kg lies on a bed of 10,000 nails. The tip of each nail has an area of 1.0 square millimeter. What pressure does the man experience? [g=10 N/kg]

*asked on April 12, 2014* -
## physics

In the javelin throw at a track-and-field event, the javelin is launched at a speed of 35.0 m/s at an angle of 33.7 ° above the horizontal. As the javelin travels upward, its velocity points above the horizontal at an angle that decreases as time passes.

*asked on January 26, 2012* -
## physics

a bullet of mass of 12 grams is fired into a large block of mass 1.5 kg suspended from light vertical wires. the bullet imbeds in the block and the whole system rises 10 cm. find the velocity of the bullet just before the collision.

*asked on June 28, 2010* -
## Physics

A rock climber hangs freely from nylon rope that is 16 m long and has a diameter of 8.1 mm. If the rope stretches 4.2 cm, what is the mass of the climber?

*asked on August 3, 2019* -
## American history

Which event led to congress declaring war against mexico? A. The siege of the Alamo B. The Whitman massacre C. The Thornton affair D. The bear flag revolt is it A?

*asked on January 8, 2019* -
## Physics

A uniform bar length of 2.0m and weight 1000 N has its center of gravity at its center. The bar is pivoted 0.5m from the right, and supports a weight of 200N on the opposite end (left end). What is the weight needed at right end of the bar to balance the

*asked on April 11, 2014* -
## Physics

The Lamborghini Murcielago can accelerate from 0 to 27.8 m/s (100 km/hr or 62.2 mi/hr) in a time of 3.40 seconds. How fast will the car be traveling (m/s) after 5.1 seconds.

*asked on February 22, 2014* -
## organic chemistry isomers

which of the following molecules has a conformational isomer? CHCH CH2CH2 CH3CH2CH2CH3 CH2CCCH2 I think its either 2 or 4 but leaning towards 4. I just need help being more confident in my answer.

*asked on April 26, 2013* -
## chemistry

a liter of a solution saturated at 25C with CaC2O4 is evaporated to dryness giving a 0.0061 gm residue of CaC2O4. Calculate the concentrations of the ions, and the molar solubility and the solubility product constant for this salt at 25C. Show the balanced

*asked on June 10, 2012* -
## physics

There are two blocks connected by a string and tied to a wall on an incline. The mass of the lower block is 1.0kg; the mass of the upper block is 2.0kg. Given that the angle of the incline is 31*, find the tension in (a) the string connecting the two

*asked on October 2, 2011* -
## Chemistry

Calculate the solubility of silver iodide in a 1.0 M sodium cyanide solution. Ksp = 8.5 x 10^-17 for AgI Kform = 2.5 x 10^5 for Ag(CN)2

*asked on April 7, 2010* -
## Chemistry

An alpha particle (mass 6.6 x 10^-24 grams) emitted by radium travels at 3.4 x 10^7 plus or minus 0.1 x 10^7 mi/h. (a) What is its de Broglie wavelength (in meters)? (b) Whats uncertainty in its position? for part (a) I got 1.53 meters which said it was

*asked on March 5, 2010* -
## chemistry

what are the symmetry elements for: cis-CoCl2(NH3)4 and trans-CoCl2(NH3)4 would it be C2 S2?

*asked on February 25, 2009* -
## physics

According to one set of measurements, the tensile strength of hair is 196 MPa, which produces a maximum strain of 0.400 in the hair. The thickness of hair varies considerably, but let's use a diameter of 50.0 u(mu)m . What is the magnitude of the force

*asked on April 18, 2008* -
## physics

A thin, light string is wrapped around the rim of a 4.00kg solid uniform disk that is 30.0cm in diameter. A person pulls on the string with a constant force of 100N tangent to the disk. Find the linear acceleration of its center of mass. If the disk is

*asked on April 12, 2008* -
## Math(check)

1)Find the range of the relation [(-1,4)},(2,5),(3,5)}.Then determine whether the relation is a funtion. 4,5,5 is the range 4,5 is a function 2)Find f(-1),if f(x)= x^2-6x/x+2 (-1)^2-6(-1)/-1+2 1+6/-1+2 7/1 =7 3)Find f(a),if f(t)= 2t^2-t-2. 2(a)^2-a-2

*asked on July 26, 2007* -
## Calculus

For an object whose velocity in ft/sec is given by v(t)=2sin(t),what is its distance,in feet, travelled on the interval t=1 to t=5?

*asked on January 27, 2019* -
## Trig

The magnitude and direction of two forces acting on an object are 100 pounds, S79degreesE, and 60 pounds N68degreesE, respectively. Find the magnitude, to the nearest tenth of a pound, and the direction angle, to the nearest tenth of a degree, of the

*asked on July 1, 2018* -
## math

Suppose you put $2000 in a savings account at an APR of 8% compounded quarterly. Fill in the table below. (Calculate the interest and compound it each quarter rather than using the compound interest formula. Round your answers to the nearest cent.) Quarter

*asked on October 24, 2017* -
## Calculus

Find all values of x if any where the tangent line to the graph of the given equation is horizontal? y= x - sqrt (x) I am very confused would I work it like this? y = x - x^-1/2 then set x = 0? Please explain. thank you!

*asked on October 2, 2014* -
## English

"I watched Hassan get raped," I said to no one. Baba stirred in his sleep. Kaka Homayoun grunted. A part of me was hoping someone would wake up and hear, so I wouldn't have to live with this lie anymore. But no one woke up and in the silence that followed,

*asked on December 2, 2012* -
## Physics

Relative to the ground, a car has a velocity of 14.8 m/s, directed due north. Relative to this car, a truck has a velocity of 24.0 m/s, directed 52.0° north of east. What is the magnitude of the truck's velocity relative to the ground?

*asked on January 26, 2012* -
## Physics

A 210 g air-track glider is attached to a spring. The glider is pushed in 12.0 cm against the spring, then released. A student with a stopwatch finds that 13 oscillations take 16.0 s. Find the spring constant k.

*asked on January 21, 2011* -
## Physics

A massless spring of constant k = 91.0 N/m is fixed on the left side of a level track. A block of mass m = 0.50 kg is pressed against the spring and compresses it a distance of d. The block (initially at rest) is then released and travels toward a circular

*asked on November 4, 2010* -
## algebra

simplify: square root of 5 + square root of 20 - square root of 27 + square root of 147. simplify: 6/4square root of 2 sqrt 5 + sqrt 20 - sqrt 27 + sqrt 147 = sqrt 5 + sqrt (4*5) - sqrt (3*9) + sqrt (49*3) = 3 sqrt 5 - 3 sqrt 3 + 7 sqrt 3 = 3 sqrt 5 + 4

*asked on August 3, 2007* -
## algebra

1)Simplify:(6x^3-16x^2+11x-5)/(3x-2) answer= 2x^2-4x+1-3over3x-2 2)Factor 27x^3-1 completley. answer= (3x-1)^3 if this isnt correct,im not sure how to solve it b/c this makes the most sense to me. 3)Simplify: x^2-3x-28 over x^2-9x+14,assume that the

*asked on August 2, 2007* -
## Stats

Running times for 400 meters is usually distributed for young men between 18 and 30 years of age with a mean of 93 seconds and a standard deviation of 16 seconds. What percent of runners with finish after 110 minutes?

*asked on April 17, 2019* -
## Chemistry please help!

Calculate (triangle)H for the following gas-phase reaction: 2 H-C (3dashes) C-H + 5 O=O --> 4 O=C=O = 2 H-O-H -Using bond energies

*asked on April 5, 2017* -
## Chemistry

Iron (III) Oxide reacts with Aluminum to form Aluminum Oxide and Iron. If I have 255 g of Aluminum and unlimited Iron (III) oxide, how many grams of Iron will form? I am really not sure how to work with this. What does it mean when it says that the iron is

*asked on January 21, 2017* -
## Microeconomics

If the price elasticity of demand is 2, this means that a __________ increase in price causes a __________ decrease in quantity demanded. A. 15%; 100% B. 15%; 10% C. 20%; 40% D. 30%; 20% answer B 15%, 10%

*asked on April 19, 2015* -
## physics

A softball player hits the ball and starts running towards first base. Draw a motion diagram, using the particle model, showing her position and her average velocity vectors for the first few seconds of her run.

*asked on August 30, 2013* -
## statistics

Consider a normal distribution with mean 20 and standard deviation 3. What is the probability a value selected at random from this distribution is greater than 20?

*asked on May 12, 2013* -
## grammar English

I am writing about interviewing Deaf Persons for my ASL research paper. The first person is Christian DeGuzman. He is profoundly deaf since birth, and about 2 or 3 years old later they found out that he was deaf that’s why. Christian grew up in Bay Area,

*asked on April 6, 2013* -
## College Physics 1

A mass is oscillating on a spring with a period of 4.60s. At t=0s the mass has zero speed is at x=8.30cm. What is the value of t the first time after t=0s that the mass is at x=4.15 cm?

*asked on November 28, 2012* -
## Chemistry

A bottle of wine contains 11.4% ethanol by volume. The density of ethanol (C2H5OH) is 0.789 g/cm3. Calculate the concentration of ethanol in wine in terms of mass percent and molality.

*asked on September 23, 2012* -
## Physics

You shoot an arrow into the air. 2.oo seconds later the arrow has gone straight upward to a height of 30 meters above its launch point. (a) What was the arrow's initial speed? (b) How long did it take for the arrow to first reach a height of 15 meters

*asked on October 1, 2011* -
## science

What mass of water, in grams, would have to be decomposed to produce 26.3 L of molecular oxygen at STP?

*asked on May 3, 2011* -
## Language Arts

In this sentence: I held it back and managed a squeaky "yes" in response. How would you correctly punctuate the yes part?

*asked on April 13, 2011* -
## Maths

Two polygons have te number of their sides in the ratio 1:3.The sums of their interior angles are in the ratio of 4;1. Find the number of sides of each polygon.

*asked on February 7, 2011* -
## Math

What is the range of y= -(x-2)^2+2 ?

*asked on December 31, 2011* -
## college physics

There are four charges, each with a magnitude of 2.0uC. Two are postive and two are negative. The charges are fixed to the corners of a 3.0m square, one to each corner, in such a way that the net force on any charge is directed toward the center of the

*asked on September 17, 2009* -
## college physics

Two small spheres, each with mass m=3g and charge q, are suspended from a point by threads of length L=0.22m. What is the charge on each sphere if the threads make an angle theta of 15 degrees with the vertical?

*asked on September 17, 2009* -
## history HHHEEELLLPPP!!!

What is the society and environment of the coastal plains?

*asked on October 9, 2008* -
## physics

In a rescue, the 64.0 kg police officer is suspended by two cables,the cable on the left made a 35 degree angle, the rope on the right made a 48 degree angle. What is the tension in the left cable? Find the tension in the right cable.

*asked on February 27, 2008* -
## MATH

HHHHHEEEEEELLLLLLLPPPPPPPP!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Find the y intercepts of these please: 1. The slope is: 6/2...3/1...3 2. The slope is: 10/2... 3. The slope is: 2/2...2 4. The slope is: 2/2...2 The formula for a slope intercept is: y = mx +

*asked on May 24, 2007* -
## Math

The graph shown represents the equation y=3x- 9 Which equation also represents the line drawn on the graph? I just need help on this, can someone please explain how to break this question down? Thank you!

*asked on February 4, 2020* -
## Chemistry

The reaction of 5.25 g of Carbon with excess O2 yields 10.2 g of CO2. What is the percent yield of this reaction?

*asked on February 20, 2019* -
## Trig

a. Find the magnitude of the force required to keep a 3100-pound car from sliding down a hill inclined at 5.7° from the horizontal. b. Find the magnitude of the force of the car against the hill.

*asked on July 14, 2018* -
## Trig

The angular speed of a point on a planet is 3pi/7 radian per hour. The equator lies on a circle of radius approximately 9000 miles. Find the linear velocity, in miles per hour, of a point on the equator.

*asked on June 2, 2018* -
## Math

Jill said that an angle is made of any to rays is she correct explain

*asked on February 27, 2018* -
## Math

The length of the top of a work bench is 5 m greater than the width. The area is 66 m^2. Find the length and the width.

*asked on February 3, 2018* -
## Chem

Suppose a runner completes a 10K (10.0 km) road race in 42 minutes and 15 seconds. What is the runner's average speed in miles per hour?

*asked on September 17, 2017* -
## Chemistry

The spectrophometer was used to measure the absorbance of each of a series of [FeSa]+ solutions. A standard curve was construnceted by plotting the absorbance vs. concentration (M). The slope and y-intercept were found to be 1496 M-1 and .003,

*asked on April 2, 2017* -
## Chemistry

Given the reaction: Fe2SiO4 (s) + 2 H2CO3 (aq) ---> 2 FeCO3 (s) + H4SiO4 (aq) how many grams of Fe2SiO4 (s) are required to completely react with 55.0 mL of .500 M H2CO3 (aq) ?

*asked on March 8, 2017* -
## Chemistry

We will calculate the amount of acid to use in each titration. Assume that you are using 0.0512 M NaOH(aq). A good volume of NaOH(aq) to use per titration is 15 mL. From this molarity and volume, the moles of NaOH can be calculated. Since the unknown acid

*asked on February 8, 2017* -
## Chemistry

The balanced equation for the synthesis of water is: 2H2 + O2 > 2H2O If I have 5.5 grams of water, at least how many grams of Oxygen gas was needed?

*asked on January 21, 2017* -
## Geometry

Carlos is making cookies. The recipe calls for 1 cup of sugar for every 3 cups of flour. Carlos has only 2 cups of flour. How much sugar should Carlos use?

*asked on January 18, 2017* -
## Math 160

The position function of an object moving along a straight line is given by s = f(t). The average velocity of the object over the time interval [a, b] is the average rate of change of f over [a, b]; its (instantaneous) velocity at t = a is the rate of

*asked on September 3, 2016* -
## English

Against which American value did the Beat generation of writers react? equality freedom individualism traditionalism***

*asked on May 2, 2016* -
## science

the density of an object with a volume of 60.0 mL and a mass of 400.0g is___? a. 0.150g/mL b. 2.89g/mL c. 5.50 g/mL or d. 6.67 g/mL

*asked on March 17, 2016* -
## Math

Find the number of the sides of a regular polygon, if the measure of one of its exterior angle is between 28 and 32.

*asked on October 3, 2014* -
## Math

If the measure of an interior angle of a regular polygon is 165, find the sum of the measures of its interior angles

*asked on October 3, 2014* -
## Math

The sum of the measures of four of the angles of a heptagon is 520. Two of the remaining three angles are congruent. The other remaining angle is 3/2 the measure of one of the two congruent angles. Find the measures of the remaining angles.

*asked on October 3, 2014* -
## Math

1. Victor brought a brand new car for 750,000. IF the value of the car depreciates 20% per year, what will it be worth during the fourth year? 2. Given the terms a10 = 3/512 and a15 = 3/16384 of a geometric sequence, find the exact value of the first term

*asked on October 3, 2014* -
## physics

A net force of 5.34 N acting for 4.23 s on a mass initial at rest, causes it to travel 4.75 m in a straight line. What is the mass?

*asked on October 2, 2014* -
## Calculus

I am so lost, I have no idea what to do next. Find the equation of the tangent line to the graph at the indicated point f(x) =x^2 +x ; a=-1 I started out using f(-1)= (-1+h)-(-1)/h but i am so lost on what to do next. I have tried to look at examples in

*asked on September 25, 2014* -
## Physics

You throw a ball downward from a window at a speed of 3.6 m/s. What will the speed of the ball be immediately before hitting the sidewalk 8.3 m below?

*asked on February 26, 2014*