# Steph

Most popular questions and responses by Steph-
## Physics

A driver of a car going 90.0km/h suddenly sees the lights of a barrier 40.0 metres ahead. It takes the driver 0.75 seconds before she applies the brakes, and the average acceleration during braking is -10.0 m/s squared. Does the car hit the barrier?SHow

*asked on February 13, 2011* -
## Chemistry

Write a balanced chemical equation for the reaction of propylamine with water. Is propylamine --> CH3CH2CH2NH2? Is the equation CH3CH2CH2NH2 + H2O --> CH3CH2CH2NH3+ + OH- right? Isn't this balanced?

*asked on November 13, 2011* -
## physics

a 200kg sailboat experiences an eastward force of 3000N by the ocean tide and a wind force against its sails with magnitude of 6000N directed toward the northwest (45 degrees north of west). what is the magnitude of the resultant acceleration?

*asked on October 23, 2008* -
## pre-calc

construction of a rain gutter: a piece of rectangular sheet metal is 20 inches wide. it is to be made into a rain gutter by turning the edges to form parallel sides. let x represent the length of each of the parallel. a) give the restrictions on x. b)

*asked on November 10, 2011* -
## Chemistry

Imagine that you mix 50 g of a solute with 100 g of water at 40 degree C. Classify each solute by whether it would completely or partially dissolve under these conditions. -KCl -KClO3 -K2Cr2O3 -KNO3 -NaNO3 -Pb(NO3)2 I need help understanding the

*asked on October 11, 2011* -
## pre-calc

analyzing the motion of a projectile: a projectile is fired from a cliff 200 feet above the water at an inclination of 45 degrees, with a muzzle velocity of 50 feet per second. the height of the projectile above the water is given by h(x)= -0.0128x^2+x+200

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

Area of a rombus: A=1/2d1d2. Solve for d1

*asked on October 30, 2012* -
## pre-calc

Physics: a ball is thrown vertically upward with an initial velocity of 80 feet per second. the distance (in feet) of the ball from the ground after t seconds if s=80t-16tt^2 a) draw the illustration b) for what time interval is the ball more than 96 feet

*asked on November 10, 2011* -
## Algebra please help

1 hour= 3,600 seconds and 1 mile=5,280 feet. Make a conjecture about how you would convert a speed of 15 miles per hour to feet per second. Then convert. Please help answer thx

*asked on November 20, 2014* -
## chemistry

A 49g piece of ice at 0.0C is added to a sample of water at 9.0C. All of the ice melts and the temperature of the water decreases to 0.0C . How many grams of water were in the sample?

*asked on September 9, 2011* -
## physics class-Help!!!

A 3.0 m rod is pivoted about its left end.A force of 6.0 N is applied perpendicular to the rod at a distance of 1.2 m from the pivot causing a ccw torque, and a force of 5.2 is applied at the end of the rod 3.0 m from the pivot. The 5.2 N is at an angle of

*asked on July 16, 2008* -
## Algebra please help out

If the number in the numerator of a unit rate is 1, what does this indicate about the equivalent unit rates? Please help answer and give an example. Thanks

*asked on November 18, 2014* -
## physics

A pendulum clock that works perfectly on Earth is taken to the Moon. (a)Does it run fast or slow there? (b) if the clock is started at 12:00:00 am, what will it read after one Earth day(24hrs)? Assume that the free-fall acceleration on the Moon is 1.63

*asked on March 21, 2007* -
## Algebra please help answer

A certain colony of bacteria triples in length every 10 minutes. It's length is now 1 millimeter. How long will it be in 40 minutes? Please help answer thx

*asked on December 15, 2014* -
## Chemistry

If you want to lose 1 pound of "fat," which is 20% water, how many kilocalories do you need to expend? i don't know where to start :( Please Help!!!

*asked on September 8, 2011* -
## algebra 1

Part A: Explain why the x-coordinates of the points where the graphs of the equations y = 4x and y = 2x−2 intersect are the solutions of the equation 4x = 2x−2. Part B: Make tables to find the solution to 4x = 2x−2. Take the integer values of x

*asked on December 11, 2017* -
## pre-calc please help!!

an open box with a volume of 1500cm cubed is to be constructed by taking a piece of cardboard of 20 cm by 40 cm, cutting squares of sides length x cm from each corner and folding up the sides. show that this can be done in two ways, and find exact

*asked on November 10, 2011* -
## Physics

At one point in a pipeline, the water's speed is 3.00 and the gauge pressure is 4.00×104 . Find the gauge pressure at a second point in the line 11.0 lower than the first if the pipe diameter at the second point is twice that at the first. I've been

*asked on January 30, 2010* -
## Physics

In the dangerous "sport" of bungee-jumping, a daring student jumps from a balloon with a specially designed elastic cord attached to his ankles, as shown in Figure P5.69. The unstretched length of the cord is 28.0 m, the student weighs 680 N, and the

*asked on October 12, 2009* -
## Math

a hollow metal sphere has an internal radius of 20cm and an external radius of 30cm , given that the density of the metal is 7.8, find the mass of the sphere , expressing your answer in kg.

*asked on July 4, 2016* -
## physics

A laboratory centrifuge on earth makes n rpm and produces an acceleration of 3.20 g at its outer end. A) What is the acceleration (in g's, i.e., acceleration divided by g) at a point halfway out to the end? B) This centrifuge is now used in a space capsule

*asked on November 26, 2010* -
## Math 1 please help

A clothing store has the sign shown in the shop window. Pani sees the sign and wants to buy 3 shirts and 2 pairs of jeans. The cost of each shirt before the discount is $12 and the cost of each pair of jeans is $19 before the discount. Question 1. Pani

*asked on January 8, 2015* -
## pre-calc

path of a frogs leap: a frog leaps from a box 3 feet high and lands 4 feet from the base of the stump. we can consider the initial position of the frog to be at (0,3) and its landing position to be at (4,0). it is determined that the height of the frog as

*asked on November 10, 2011* -
## Algebra

What is the result if you multiply a number of cups by 8 fl oz/ 1 cup and then multiply the result by 1 cup/ 8 fl oz? Give an example thx

*asked on November 19, 2014* -
## chemistry

MnO2+4HCl-->MnCl2+2H20+Cl2 a. calculate the mass of MnO2 needed to produce 25 g of Cl2 b. what mass of MnCl2 is produced when 0.091 g of Cl2 is generated?

*asked on May 28, 2012* -
## chemistry

4. A sulfuric acid solution containing 571.6 g of H2SO4 per liter of solution has a density of 1.329 g/cm3 . Calculate a. The mass percentage b. The mole fraction c. The molality d. The molarity of H2SO4 in this solution

*asked on February 5, 2015* -
## Physics

On a cold winter day, a penny (mass 2.50 g) and a nickel (mass 5.00 g) are lying on the smooth (frictionless) surface of a frozen lake. With your finger, you flick the penny toward the nickel with a speed of 2.50 m/s . The coins collide elastically;

*asked on November 24, 2017* -
## Chemistry

You are in a mountain range with atmospheric air pressure of 520 mmHg , and you wish to boil some eggs. What is the approximate boiling point of the water at this air pressure?

*asked on October 4, 2011* -
## Chemistry

Lead has a melting point of 327ºC, its specific heat is J/g•deg, and its molar enthalpy of fusion is 4.80 kJ/mol. How much heat, in kilojoules, will be required to heat a 500.0-g sample of lead from 23.0ºC to its melting point and then melt it?

*asked on November 4, 2012* -
## Finite

Assume that the pond contains 120 fish: 97 green, 22 yellow, and 1 red. A contestant pays $0.60 to randomly catch one fish and receives $0.40 if the fish is green, $0.95 if the fish is yellow, and $11.00 if the fish is red. How much (on average) does the

*asked on October 13, 2015* -
## organic chemistry

a 50% aqueous solution of ethanol (50mL total) is distilled and collected in 10-mL fractions. Predict the boiling range of each fraction

*asked on October 11, 2010* -
## Physics

The space shuttle releases a space telescope into orbit around the earth. The telescope is traveling at a speed of 1700m/s in 25 seconds. What is the distance of the satellite? d = v x t d = 1700 x 25 = Is that the correct formula? Thank you.

*asked on May 8, 2015* -
## Algebra

Barbara can walk 3200 meters in 24 minutes. How far can she walk in 3 minutes?

*asked on December 10, 2014* -
## Chemistry

Lead has a melting point of 327ºC, its specific heat is J/g•deg, and its molar enthalpy of fusion is 4.80 kJ/mol. How much heat, in kilojoules, will be required to heat a 500.0-g sample of lead from 23.0ºC to its melting point and then melt it?

*asked on November 4, 2012* -
## math

how to write a verbal expression for 3x^2 and 5 + 6m^3

*asked on September 5, 2012* -
## Statistics

18. The Intelligence Quotient (IQ) test scores are normally distributed with a mean of 100 and a standard deviation of 15. Given a class with 25 students, what is the probability that the class' average IQ score is between 85 and 115? A) 0.0026 B) 0.4987

*asked on October 22, 2011* -
## AP Chemistry

what is the pH of a solution that is 0.060 M in potassium propionate and 0.085 M in propioic acid

*asked on March 22, 2011* -
## chem

Write the equilibrium expression for the following: 2NOCl (g) ==== 2 NO + Cl2 (g)

*asked on March 1, 2015* -
## physics

A 56.0 ice skater spins about a vertical axis through her body with her arms horizontally outstretched, making 2.00 turns each second. The distance from one hand to the other is 1.5 . Biometric measurements indicate that each hand typically makes up about

*asked on November 8, 2010* -
## Physics

The speed of light is about 3.00 x 10 to the power of 5 km/s. It takes approx. 1.28 seconds for light reflected from the moon to reach Earth. What is the average distance from Earth to the moon? Thank you

*asked on May 8, 2015* -
## Chemistry

The Vitamin C content claimed on the product label is that 1 cup of juice contains 130% of the recommended daily allowance (RDA) for vitamin C? Based on the product label claimed, how many milliliters of this juice must an adult drink to obtain the

*asked on October 3, 2011* -
## math

pamela is shopping for bottled water at the supermarket. which is the best buy? A 1 2-liter bottle for 0.89 B 3 1-liter bottles for 1.50 ** C 24 0.5 liter bottles for 5.25 D 36 0.025-liter bottlesfor 4.75

*asked on May 10, 2019* -
## science

Calculate the molarity of a solution which contains 6.456g of Na2CO3 dissolved in 250.0 ml of solution.

*asked on February 1, 2015* -
## pre- calc

area of a parking lot: One campus of Houston community college has plans to construct a rectangular parking lot on land bordered on one side by a highway. there are 640 feet of fencing available to fence the sides. let x represent the length of each off

*asked on November 10, 2011* -
## chemistry

When carbon is burned in air, it reacts with oxygen to form carbon dioxide. When 25.2g of carbon were burned in the presence of 78.0g of oxygen, 10.8g of oxygen remained unreacted. What mass of carbon dioxide was produced?

*asked on September 7, 2011* -
## MATH PLEASE HELP

A certain molecule contains twice as many atoms of hydrogen as oxygen and one more atom of carbon than hydrogen. If there are 31 atoms altogether in the molecule. how many atoms of carbon are there?

*asked on October 19, 2010* -
## Statistics

Scores on an IQ test are normally distributed. A sample of 15 IQ scores had standard deviation s=10. The developer of the test claims that the population standard deviation is =15. Do these data provide sufficient evidence to contradict this claim? Use

*asked on March 12, 2019* -
## English

Need help editing an essay. Am I in the right place? TIA! :)

*asked on December 11, 2018* -
## CHEM

The mass of an evacuated 255-mL flask is 143.187g. The mass of the flask filled with 267 torr of an unknown gas at 25 degrees Celsius is 143.289g. Calculate the molar mass of the unknown gas.

*asked on July 22, 2008* -
## re

i have similar homework to leigh about miracles. i need to give 3 reasons why miracles occur,this is what ive thought of:- .praying .believing in God .faith im still struggling to think of 3 reasons why miracles do not occur. thanks

*asked on June 10, 2009* -
## Algebra

How many 0.6 liter glasses can you fill up with a 4.5 liter pitcher?

*asked on December 10, 2014* -
## Math

The heights of three plants A,B and C in a garden are in the ratio 2 : 3 :5. their mean height is 30cm a) find the height of plant b b) if another plant D is added to the garden and the mean height of the four plant is now 33cm , find the height of D plant

*asked on July 4, 2016* -
## Math please help out

What are the dimensions of a football field in feet? If one side is 53 1/3 yards and the other is 120 yards? Please help answer B. A chalk line is placed around the perimeter of the football field. What is the length of this line in feet? C. About how many

*asked on November 19, 2014* -
## Chemistry

An aqueous solution of NaCl freezes at -1.6ºC. At what temperature will it boil? Given that K(b) for water is 0.52 deg m^-1.

*asked on April 17, 2013* -
## Chemistry

Why water can be used as a solvent in paper chromatography?

*asked on July 14, 2016* -
## Physics

An observer stands 43.0 m behind a marksmen practicing at a rifle range. The marksman fires the rifle horizontally which gives the speed of the bullet to be 939 m/s. How far does each bullet travel before the observer hears the report of the rifle? Assume

*asked on March 13, 2011* -
## Chemistry

A student collected concentration data to determine the rate of the decomposition of N2O5 to NO2 and O2. The data were recorded in the table below. What is the rate law of this reaction? k[N2O5] k[N2O5]2 k k[NO2]

*asked on March 10, 2016* -
## chemistry

You perform the following titration: You placed 35 mL of H2S in a flask and placed it under a buret. The buret contains 0.243M Sr(OH)2 and you are going to titrate the H2S with the base. You titrate until the color changes. At that point, you record that

*asked on November 14, 2014* -
## Statistics

Suppose x has a mound-shaped distribution with sigma = 9 . A random sample of size 36 has sample mean 20. Is it appropriate to use a normal distribution to compute a confidence interval for the population mean m? Explain. Find a 95% confidence interval for

*asked on April 27, 2013* -
## chemistry

In an acid-base titration, 33.12ml of 0.1177 M H2C2O4 was titrated with 0.2146 M NaOH to the end point. What volume of the NaOH solution was used?

*asked on February 1, 2015* -
## pre-calc

area of a rectangular region: a farmer wishes to create two rectangular regions bordering a river, by three fences perpendicular to the river and one connecting them. suppose that x represents the length of each of the three parallel pieces of fencing. she

*asked on November 10, 2011* -
## Chem 12

0.300 mol of S2 and 0.310 mol of C are placed in a 1.00 L flask and allowed to reach equilibrium according to this reaction: S2(g) + C(s) ⇔ CS2(g) At equilibrium, 0.271 mol of CS2 is present. The value of Keq for the reaction is ---- a)9.3 b)0.91 c)240

*asked on April 4, 2015* -
## physics

A hunter aims directly at a target (on the same level) 85.0 away. If the bullet leaves the gun at a speed of 188 , by how much will it miss the target?

*asked on November 23, 2010* -
## Social Studies

What were seven weaknesses of the articles of confederation(please answer quick) .Not strong federal government .strong state government

*asked on December 8, 2015* -
## chem II

0.959 g of a hydrocarbon is dissolved in 10.00g of benzene. The freezing point of the solution is 1.16C. Find the molecular mass of the hydrocarbon. Benzene has a Kf of 5.12 and a freezing points of 5.53 degrees C. Not sure how to go about solving this

*asked on February 8, 2015* -
## Science

What is the main method of heat transfer from the core to the crust of earth? A. Conduction B. Convection C. Radiation

*asked on January 12, 2015* -
## math

you are driving to a vacation spot that is 1500 miles away. Including rest stops, it takes you 42 hours to get to the vacation spot. You estimate that you drove at an average speed of 50 miles per hour. How many hours were you not driving?

*asked on October 17, 2012* -
## physics

A bicycle is moving at 8.3 m/s. What is the angular speed of its tires if their radius is 42 cm?

*asked on October 22, 2007* -
## Journal Entry of a Subordinate Group Member

Subordinate Groups: Native Americans, African Americans, Chinese Americans, Japanese Americans, Arab Americans, Filipino Americans, Korean Americans, Vietnamese Americans, Asian Indians, Hawaiians, Irish Americans, Polish Americans, Norwegian Americans,

*asked on August 26, 2007* -
## math

There were 3 times as many adults as students attending a school play. If the attendance was 480, how many adults and how many students attended the play? Let x equal the number of students attending the school play and solve this equation. 3x + x = 480

*asked on August 9, 2007* -
## Physics

A block attached to a spring is displaced from equilibrium to the position x=+2.8m and released. The period is 1.6s . At what positions and times during the first complete cycle do the following conditions occur. a) |v|=0.5vmax, Where vmax is the maximum

*asked on September 5, 2019* -
## chem

The solution of known concentration to use to evaluate Z was prepared as follows: 2.00mL of 0.00201 M KSCN and 18.0 ml 0.200 M Fe (NO3)3. Assume that all of the SCN- has been converted to Fe(SCN)2t in this solution. Fe3+ SCN- ==== Fe Fe(SCN)2+ I don't

*asked on March 1, 2015* -
## physics

A shotputter throws the shot with an initial speed of 16.0 m/s at a 36.0 angle to the horizontal. Calculate the horizontal distance traveled by the shot if it leaves the athlete's hand at a height of 2.00 m above the ground

*asked on November 23, 2010* -
## College Physics!!!

A truck on a straight road starts from rest accelerating at 2.0 m/s2 until it reaches a speed of 20 m/s. Then the truck travels for 20 s at constant speed until the brakes are applied, stopping the truck in a uniform manner in an additional 5.0 s. What is

*asked on October 6, 2008* -
## Statistics

28. A group of statistics students decided to conduct a survey at their university to find the average (mean) amount of time students spend studying per week. Based on a simple random sample, they surveyed 144 students. The statistics showed that students

*asked on October 22, 2011* -
## math

Marcy is planning to borrow $12,500 with a simple interest rate of 5.2% for 4 years. How much will she pay back to the bank?

*asked on March 9, 2011* -
## math

The length of a rectangle is 5cm more than twice the width. The perimeter of the rectangle is 34 cm. Find the dimensions of the rectangle. So confused on how to do this problem please help me thanks.

*asked on March 13, 2013* -
## Physics

A driver in a car traveling at a speed of 72 km/h sees a cat 107 m away on the road. How long will it take for the car to accelerate uniformly to a stop in exactly 104 m?

*asked on March 2, 2014* -
## physics

A person standing at the edge of a seaside cliff kicks a stone over the edge with a speed of vi = 11 m/s. The cliff is h = 47 m above the water's surface, as shown below.

*asked on September 27, 2009* -
## Algebra please help out

In Beijing in 2008, the women's 3,000 meter steeplechase became an Olympic event. What is this distance in kilometers? Please help answer thx

*asked on November 19, 2014* -
## Math / Physics

Many birds drop clams or other shell fish in order to break the shell and get the food inside. Suppose a crow drops a shell from a height of 5.2m. How long does it take to reach the ground?

*asked on February 15, 2012* -
## Math

The dimensions of a rectangular pool are 28.4 feet by 18 feet. The depth is 5 feet. Each cubic foot contains approximately 7.5 gallons of water. How many gallons of water will it take to fill the pool 60% full?

*asked on April 24, 2019* -
## AP Calculus

Consider the function f(x) = 1/4x^4 - 5/3x^3 - 3/2x^2 + 15x - 3. A. Find the relative extrema for f(x); be sure to label each as a maximum or minimum. You do not need to find function values; just find the x-values. B. Determine the interval(s) where f(x)

*asked on January 16, 2017* -
## Math

An automobile purchased for 24000 is worth 2100 after 8 years. Assuming that the car's value depriciated steadily from year to year, what was it worth at the end of the third year?

*asked on February 3, 2009* -
## physics

Given that x=Acos(wt) is a sinusoidal function of time, show that v(velocity) and a(acceleration) are also sinusoidal functions of time. (HINT: Use v=square root [(k/m)(A^2-x^2)] and a=(-k/m)X The hint tells you what to do: put Acoswt for X. A second way

*asked on March 15, 2007* -
## Calc

A cardboard box manufacturer makes open boxes from rectangular pieces of cardboard of size 30cm by 40cm by cutting squares from the four corners and turning up the sides. A) find a mathematical model expressing the volume of the box as a function of the

*asked on September 25, 2013* -
## Math

A rectangle park measures 300 ft by 400 ft. A sidewalk runs diagonally from one corner to the opposite corner. Find the length of the sidewalk.

*asked on May 1, 2011* -
## Arithmetic Progressions

The second term of an arithmetic progression I four times the fits term, and the first term is ten. Find the common difference and hence find the sum of the first 12 terms.

*asked on March 10, 2015* -
## chemistry II

What is the molarity of a solution of acetic acid if 35.00mL is titrated to the end point with 68.20ml of 0.750M KOH? What is the percentage by mass of acetic acid solution? The density of acetic acid is 1.06 g/ml

*asked on February 1, 2015* -
## Algebra

If n(A U B)=22, n(A ∩ B)=8, and n(B)=12, find n(A) If n(A)=8, n(B)=14 and n(A ∩ B)=5, find n(A U B)

*asked on September 13, 2012* -
## Chemistry

Asprin, c9h804, is produced through the following reaction of salicyclic acid, c7h6o3, and acetic anhydride, c4h6o3. chemical equation: c7h6o3 + c4h6o3 yields c9h8o4 + hc2h3o2 (all numbers in this equation are subscripts) At 20 degrees Celsius. how many

*asked on January 21, 2007* -
## math 9

in a park some people are launching model rockets to find the maximum height,x,the rocket reaches, a person stands 50.0m from the launch sight and measure the angle from the ground to the rocket at its maximum height. if the angle is 36 then the maximum

*asked on June 17, 2010* -
## Statistics

About 74% of young adult Internet users (aged 18 to 29) use social network sites. Suppose that a sample survey contacts an SRS of 2000 young adult Internet users and calculates the proportion p̂ in this sample who use social network sites.

*asked on November 29, 2016* -
## PHYSICS

Jason is practicing his tennis stroke by hitting balls against a wall. The ball leaves his racquet at a height of 57 cm above the ground at an angle of 80° with respect to the vertical. (a) The speed of the ball as it leaves the racquet is 17 m/s and it

*asked on October 16, 2007* -
## PHYSICS

A ball is thrown from a point 1.2 m above the ground. The initial velocity is 19.8 m/s at an angle of 34.0° above the horizontal. (a) Find the maximum height of the ball above the ground. (b) Calculate the speed of the ball at the highest point in the

*asked on October 16, 2007* -
## algebra

What is the measure of the length of a rectangle with a width of 3x + 4y + 1 and a perimeter of 24x + 18y + 32?

*asked on December 19, 2011* -
## physics

A hunter aims directly at a target (on the same level) 85.0 m away. If the bullet leaves the gun at a speed of 188 m/s, by how much will it miss the target?

*asked on November 23, 2010* -
## Physics

Write 2.38x10 to the 6th power in standard notation

*asked on August 31, 2016* -
## PHYSICS VOLUME QUESTION!

You are watering your lawn with a hose when you put your finger over the hose opening to increase the distance the water reaches. If you are pointing the hose at the same angle and the distance the water reaches increases by a factor of 4, what fraction of

*asked on April 27, 2016* -
## Physics

A person looking out the window of a stationary train notices that raindrops are falling vertically down at a speed of 3.6 m/s relative to the ground. When the train moves at a constant velocity, the raindrops make an angle of 60° when they move past the

*asked on February 16, 2014*