# Posts by john

Total # Posts: 8,426

**Physics**

Two springs are set up on a table. The longer spring has a spring constant of 221 N/m and an initial length of 44.0cm. The shorter spring has a spring constant of 725 N/m and an initial length of 22.0cm. How far above the table is an 9.30kg ball when it reaches its equilibrium...

**Physics**

while walking behind a horse, a rancher walks 18.0 m (290degrees), then 25.0 m (340degrees) and finally 14.0 m (130 degrees) A)Calculate the displacement of the rancher b) if the rancher walks for 10 min, what is the average velocity of the walk?

**English**

Thankyou

**English**

What event (or events) mainly caused the fall of the British Empire? A. World War II B. the colonies rose up and fought back against the empire C. infighting between the British leaders caused it to implode from within D. both World War I and World War II My first choice (a.) ...

**Accounting, Business Studies, Economics and Maths Lit**

we do something like every day make sure you read books you will could get marks

**chem equilibrium**

Determine the pH of a buffer that is prepared by mixing 100 mL of 0.2 M NaOH and 150 mL of 0.4 M acetic acid assuming the volume is additive. Calculate the pH of the solution when 0.5 mL of 1 M of HCl was added hence calculate the buffer capacity.(Given:pKa of acetic acid = 4....

**math**

A meat department manager discovrs that she can sell m(x) killograms of ground beef in a week, where m(x) = 14 700 - 3040x, if she sells it at x dollars per kilogram. She pays her supplier $3.21/kg for the beef. a) Determine an algebraic expression for P(x), where P(x) ...

**Physics**

A 0.01 kg Styrofoam ball is released from rest 2m above the floor. It reaches a speed of 3m/s the moment before it hits the floor. How much heat due to air resistance is generated during this process?

**Calculus**

A spherical balloon is being inflated so that, at the time when the radius is 5m, the radius is increasing at the rate of 0.15m/s. (A) Find the rate of increase of the volume at this time. (B) If the rate of increase of volume thereafter remains constant, find the rate at ...

**math**

x = amount at 4% 10,000 -x = amount at 3% I = Prt Interest for amount at 4% is .04x since time is 1. Interest at 3% is .03(10000-x) the 4% interest is $246 more .04x = .03(10000-x) +246

**science**

The range is always a maximum if the angle is 45 degrees.

**Algebra**

Usually, time would be on the x-axis. slope is change in y/change in x slope = (6-4)/(45-30) slope = 2/15 miles/minute

**Algebra**

We need to see the graph. An easy way to make a match is to look for the intercepts and to check the slope. To make the equation easier to work with, I would multiply through by a -12 8x + 3y = -4 If x = 0 they y = -4/3 If y = 0 then x = -1/2 look for the points (0, -4/3) and...

**Physics**

never mind, i think i found my mistake. 521m/s is the final velocity, not initial. thanks guys

**Physics**

A bullet leaves a rifle with a muzzle velocity of 521 m/s. While accelerating through the barrel of the rifle, the bullet moves a distance of 0.840 m in 0.003 seconds. Determine the acceleration of the bullet. So I basically used the formula: Change in position= (Initial ...

**Algebra**

Draw the graph of y = 6x by filling in the table below. X| y = 6x ---------- -2| -1| 0| 1| 2| Domain = ? Range = ?

**Math**

if i have read 150 pages of a 240 page book, what percentage of the book have I read?

**Math**

In the expression ln(3-x)+ln(3+x) what is the highest possible number that x can be? I got to this point: ln(9-x^2) but what now? it seems to me that there is an asymptote at x = 3, so the answer is 2.9999999... but it can't be repeating because that would make it 3, ...

**Algebra**

Use the formula pH = −log[H^+] 9.. The hydrogen ion concentration of a substance is 4.3*10^-6 × moles per liter.Find the pH. Round to the nearest tenth. 10. Find the hydrogen ion concentration of a solution whose pH is 5.3.

**Math**

a plane flies 1.5 hours at 110 mph on a bearing of 10°. it then turns and flies 8.5 hours at the same speed on a bearing of 100°. How far is the plane from its starting point?

**Algebra**

Richey Loaner inherited $2105.22 from a not-so-rich uncle. If Richie deposits his money into an account that pays 3% compounded continuously for t years, then the function A(t)=2105.22e^0.03t gives the account balance after t years. (a) Find Richie’s account balance 6 ...

**Chemistry**

is delta S positive for the heating of water from 25 to 75 degrees Celsius?

**Physics**

How do you calculate V^2 ?

**Physics**

Thanks Damon

**Physics**

An arrow is fired horizontally at a speed of 50m/s from the top of a vertical cliff overlooking the sea. The height of the cliff is 12m. Determine The speed and angle to the horizontal of the arrow when it enters the sea?

**Mathematics**

An arrow is fired horizontally at a speed of 50m/s from the top of a vertical cliff overlooking the sea. The height of the cliff is 12m. Determine The speed and angle to the horizontal of the arrow when it enters the sea?

**maths**

0.6 of the children in a club are girls, if there are 27 girls, how many children are there

**Algebra**

Find the missing coordinate if (-2/3, is a solution of -6x + 7y = 11

**Physics**

I cant tell if ur srs or not? This seems like some taliban stuff

**chemistry**

Help me solve it. Step by step please The value of kp at 20°c for the reaction 2NO(g) +Cl2(g) 2NOCl(g) is 1.9x10^3 atm-1 calculate the value of KC at the same temperature.

**Physics**

A gas cylinder has a volume on 200l, and contains Nitrogen at a pressure of 200kPa and a temperature of 290 degrees Kelvin. The molar mass of Nitrogen is 14.0067g. Calculate. The number of moles in the gas cylinder?

**Chemistry**

The highest temperature ever recorded in Palm Desert, California, was 122„aF. Express this temperature in degrees Kelvin.

**Mathematics**

Determine the points of intersection of the curve: y=(7-4x)/(x-4) and the line y=2x-1

**Math**

Tickets to science exposition cost $5.75 each for students and $7.00 for adults. How many students and adults went if the ticket charge was $42.75?

**math**

A company has a policy of retiring company cars; this policy looks at number of miles driven, purpose of trips, style of car and other features. The distribution of the number of months in service for the fleet of cars is bell-shaped and has a mean of 55 months and a standard ...

**math**

A company has a policy of retiring company cars; this policy looks at number of miles driven, purpose of trips, style of car and other features. The distribution of the number of months in service for the fleet of cars is bell-shaped and has a mean of 55 months and a standard ...

**math**

A company has a policy of retiring company cars; this policy looks at number of miles driven, purpose of trips, style of car and other features. The distribution of the number of months in service for the fleet of cars is bell-shaped and has a mean of 56 months and a standard ...

**math**

The average resting heart rate of a population is 89 beats per minute, with a standard deviation of 13 bpm. Find the z-scores that correspond to each of the following heart rates. Round your answers to the nearest hundredth, if necessary. (a) 95 bpm Z= (b) 69 bpm Z=

**math**

The average resting heart rate of a population is 89 beats per minute, with a standard deviation of 13 bpm. Find the z-scores that correspond to each of the following heart rates. Round your answers to the nearest hundredth, if necessary. (a) 95 bpm Z= (b) 69 bpm Z=

**math**

Alicia Martin's savings account has a principal of $1,200. It earns 6% interest compounded quarterly for two quarters

**Statistic**

an insurance policy sells for $700. based on past data, an average of 1 in 80 policyholders will file a $10,000 claim, an average of 1 in 120 policyholders will file a $20,000 claim, and an average of 1 in 200 policyholders will file a $50,000 claim. what is the expected value...

**Programming**

Declare Integer count For count=1 to 3 Step 2 Display count End For What would the output be?

**Algebra**

Year Number of Graduates (in millions) 2009 15.4 2010 15.9 2011 16.3 2012 16 2013 15.7 a. Code the years using t = 1 for 2009 and fit a quadratic function to the data with the regression program on your calculator. equation is ________________________________ b. Predict the # ...

**Physics**

What is the mass of a copper wire that will give a wire, 0.20mm in diameter, a resistance of 400 ohms can you please show me the formulas

**Physics**

Three charges are located along the x axis as shown in the drawing. The mass of the -1.2 uC is 4.0×10^-9 kg. Determine the magnitude and direction of the acceleration of the -1.2 uC charge when it is allowed to move if the other two charges remain fixed. I need help ...

**Algebra**

9.The following table gives the number of graduates in health professions in the U.S. for various years. Year Number of Graduates (in millions) 2009 |15.4 2010 |15.9 2011 |16.3 2012 |16 2013 |15.7 a. Code the years using t = 1 for 2009 and fit a quadratic function to the data ...

**Algebra**

The Yellow Pencil Company sells the best pencils ever made. If the cost of producing x hundred pencils is given by C(x)=0.4x^2-29x+44 and if the revenue generated from the sale of x hundred pencils is R(x)=-0.6x^2+19x. Money is in thousands of dollars. (a) Show all work to ...

**Algebra**

During the first part of a canoe trip, May paddled 20 km up steam and 20 km back in a total time of 5 hrs. The speed of the river is 3 km/hr. Find May’s speed in still water. Set up the equation first then solve.

**Algebra**

The Yellow Pencil Company sells the best pencils ever made. If the cost of producing x hundred pencils is given by C x x x ( ) 0.4 29 44 = − + 2 and if the revenue generated from the sale of x hundred pencils is R x x x ( ) 0.6 19 = − + 2 . Money is in thousands of...

**Algebra**

The distance traveled by an object moving in a straight line is given by s = t2 − 2t, where s is in feet and t is the time in seconds the object has been in motion. How long (to the nearest tenth) will it take the object to move 48 feet?

**Chemistry**

Why is Hydrogen sulfate amphiprotic?

**math**

write 2.18 as a mixed number in simplest form

**Pre-Algebra**

A ball is thrown straight up at 46 feet per second from about 6 feet above the ground. How long will it take for the ball to reach a height of 39 feet?

**Physics**

Using the data in the table below,determine how many calories are needed to change 100g of solid x at 10degrees celcious to a vapour at 210degrees celcious:thermodynamic constants for substance x: heat of fusion 40,0cal/g heat of vaporization 150,0cal/g melting point 10,0'...

**Philosophy**

In her book The Beauty Myth author Naomi Wolf argued that women harm themselves when they try to live up to the standards of beauty implied in most commercial advertising. The following excerpt is taken from a World Press Review commentary on Wolf’s work: [S]omething that...

**science**

A boy complains of stomach pain to his mother. Unable to resolve the issue herself, she takes the boy to the doctor. Which of the following might be a good hypothesis for the stomach pain?The boy fell and hurt his stomach. The boy has an infection and needs antibiotics. The ...

**functions**

Andrew is 5 years older than Tim. Tim is aged 19. Write an equation for x, where x is the age of Andrew. Solve the equation.

**Algebra 2**

How do I find z (or any other variable for that matter)? −2z + 6 + 2(z+1) = 14 −2z + 6 + 2z + 2 = 14 8 = 14 I try to solve the equation but end up with this, which is false.

**Algebra 2**

Solve by Substitution x + 2y + z = 14 y = z + 1 x = -3z + 6

**Chemistry**

What is the pH of a solution resulting from the addition of 10.0 mL of 0.17 M HCl to 50.0 mL of 0.16 M NH3? Assume the volumes are additive. Kb of NH3 = 1.8 ✕ 10-5.

**english**

Which revision changes a verb in the sentence to the subjunctive mood? Some colleges require that each potential student completes an essay.

**Math**

Show that the equation tanθ = sinθ can be written in the form sinθ(1 - 5cosθ) = 0?

**Physical science**

A train with a mass of 200,000 kg manages to brake to a speed of 3 m/sec before colliding with a truck with a mass of 2,000 kg that is stuck on the track. What speed does the truck move away from the train.

**EFA**

write a cubic equation whose integral coefficient roots are -5 and radical 2

**algebra help!**

So the answer 40

**Algebra**

Divide and reduce to lowest terms wherever possible. 105/ 5+1/4

**Math homework**

1-(1/6)-(2/5) = (5/6)-(2/5) = ((25-12)/30) = 13/30

**Integral Calculus - Series**

Find if series is convergent or divergent. Series from n=2 to infinity (4n+7)/(3n^3 -8n)

**Math**

Thank you

**Math**

An airplane flys at a constant altitude of 2 miles and a constant speed of 600 miles per hour on a straight course that will take it directly over a kangaroo on the ground. How fast is the angle of elevation of the kangaroo's line of sight increasing when the distance ...

**math-linear algebra**

Determine which of the following mappings are linear mappings. A. The mapping L defined by L(x_1, x_2 ) = (4x_1- 2x_2, 3 |x_2|). B. The mapping L defined by L(x_1, x_2 ) = (2x_1-3x_2, x_1+4, 5x_2). C. The mapping L defined by L(x_1, x_2, x_3 ) =(x_1, 0 , x_3). D. The mapping L...

**math-linear algebra**

Determine the standard matrix A of the linear mapping L:R^2-->R^2 that rotates any vector through an angle of 150 degrees in the clockwise direction.

**math-linear algebra**

Determine the standard matrix D of the linear mapping G: R^2--R^2 that first rotates points clockwise through pi/6 radians and then reflects points through the line x_2=x_1

**Physics**

Air consists of molecules of several types, with an average molar mass of 28.95g. About how many molecules does an adult who inhales 0.50L of air at sea level take in? The answer should be 1.3x10^22

**math**

2x - 6 = 20. Add 6 to both sides. 20 + 6 = 26 26÷2 =13

**math**

[2(X+26)]/2=264/2 X+26=132 X+26-26=132-26 X=106

**physics**

A puck (mass m1 = 2.20 kg) slides on a frictionless table as shown in the figure below. The puck is tied to a string that runs through a hole in the table and is attached to a mass m2 = 6.6 kg. The mass m2 is initially at a height of h = 6.6 m above the floor with the puck ...

**physics**

A child of mass 52 kg jumps onto the edge of a merry-go-round of mass 170 kg and radius 1.9 m that is initially at rest as sketched in the figure below. While in the air (during her jump), the child's linear velocity in the direction tangent to the edge of the merry-go-...

**physics**

The drawing shows a skateboarder moving at 6.88 m/s along a horizontal section of a track that is slanted upward by 37.3 ° above the horizontal at its end, which is 0.741 m above the ground. When she leaves the track, she follows the characteristic path of projectile ...

**Organic Chemistry 2**

What is the impurity that must be removed from the benzaldehyde reagent before it can be used in this experiment? this is from are Benzil lab

**Organic Chemistry 2**

Compare the IR spectrum of benzoin ) with the IR spectrum of benzil . Explain how the changes in the important peaks are related to the differences between the two structures.

**math**

Every cereal box has a gift inside, but you cannot tell from the outside what the gift is. The store manager assures you that 16 of the 58 boxes on the shelf have the secret decoder ring. The other 42 boxes on the shelf have a different gift inside. If you randomly select two ...

**math**

In a family with 4 children what is the probability of having 1 boy and then 3 girls, in that order? (Exclude multiple births and assume all outcomes are equally likely). In a family with 4 children, what is the probability of having 1 boy and 3 girls, in any order? (Exclude ...

**math**

A hacker is trying to guess someone's password. The hacker knows (somehow) that the password is 14 characters long, and that each character is either a lowercase letter, (a, b, c, etc), an uppercase letter (A, B, C, etc) or a numerical digit (0, 1, 2, 3, 4, 5, 6, 7, 8, or ...

**math**

A hacker is trying to guess someone's password. The hacker knows (somehow) that the password is 14 characters long, and that each character is either a lowercase letter, (a, b, c, etc), an uppercase letter (A, B, C, etc) or a numerical digit (0, 1, 2, 3, 4, 5, 6, 7, 8, or ...

**math**

A couple plans to have three children. What is the probability that. a) they have all boys? b) they have at least one girl?

**Organic Chemistry 2**

What is the impurity that must be removed from the benzaldehyde reagent before it can be used in this experiment? this is from are Benzil lab in this lab, benzoin condensation of benzaldehyde will be carried out with a biological coenzyme, thiamine hydrochloride, as the ...

**Organic Chemistry 2**

What is the purpose of adding NaOH ot the reaction? This is the from our Benzil Lab.

**Organic Chemistry 2**

Compare the IR spectrum of benzoin ) with the IR spectrum of benzil . Explain how the changes in the important peaks are related to the differences between the two structures.

**Organic Chemistry 2**

Compare the IR spectrum of benzoin ) with the IR spectrum of benzil . Explain how the changes in the important peaks are related to the differences between the two structures.

**Organic Chemistry 2**

What is the purpose of adding NaOH ot the reaction? This is the from our Benzil Lab.

**Organic Chemistry 2**

Isolation of crude Benzoind-allow about 5 minutes for the crystals of benzoin to form fully. place the flask, with crystals, into an ice bath for 5-10 minutes. Break up the crystalline mass with a spatula, swirl the flask rapidly and quickly transfer the benzoin to a hirsch ...

**Organic Chemistry 2**

Procdure. Reaction Mixture-Add 0.3 g of thiamine hydrochloride to a erlenmeyer flask. Dissolve the solid in 0.45 mL of water by swirling the flask. Add 3.0 mL of 95% ethanol, and swirl the solution until it is homogeneous. To this solution add 0.9 mL of an aqueous sodium ...

**Organic Chemistry 2**

umm in this lab, benzoin condensation of benzaldehyde will be carried out with a biological coenzyme, thiamine hydrochloride, as the catalyst:

**Organic Chemistry 2**

What is the impurity that must be removed from the benzaldehyde reagent before it can be used in this experiment? this is from are Benzil lab

**Physics**

The propeller blades of an airplane are 2.4 m long. The plane is getting ready for takeoff, and the propeller starts turning from rest at a constant angular acceleration. The propeller blades go through two revolutions between the fifth and the seventh second of the rotation. ...

**Math**

9/16 x 2/3 =

**math 8th grade**

for a project, you need the diagonal fold of a square piece of origami paper to be 10 cm long. to what dimensions do you need to cut the square origami paper?

**math 8th grade**

a black 8" tile was cut to surround a white 8" tile. what is the perimeter of the design?

**math 8th grade**

what is the height of an equilateral triangle with an edge of one meter?