Friday
February 12, 2016

# Posts by Bill

Total # Posts: 793

physics
A rocket blasts off from rest and attains a speed of 49 m/s in 16 s. An astronaut has a mass of 56.3 kg. What is the astronaut's apparent weight during take off?
February 8, 2016

Physics
A 1000-kg aircraft going 25 m/s collides with a 1500-kg aircraft that is parked. They stick together after the collision and are moving at 10 m/s. If they skid for 30 seconds before stopping, how far (in meters) did they skid? Hint: Are the aircraft moving at a constant ...
January 30, 2016

Chemistry
9.299 grams
January 26, 2016

Chemistry
Molar mass of H2O = 18.0 g/mol 18 g ------> 6.02x10^23 atoms g -------> 3.11x10^23 atoms ( 3.11x10^23) * 18 / 6.02x10^23 5.598x10^24 / 6.02x10^23 = 9.299 gramas hope thi helps!.
January 26, 2016

Chemistry
Percent of gas (C2H2 ) formed.
January 26, 2016

Chemistry
What is the percentage of gas (C2H2) formed when 2.66g of calcium carbide (CaC2) reacts completely with 50g water?
January 26, 2016

math
how long would it take a car traveling 175 mph to go 26 miles?
January 24, 2016

Chemistry
Calculate the equilibrium constant for the equilibrium knowing that there are 2 moles of O2 H2, 6 moles of O2 and 3 moles of H2O in a jar reactor 2L? 2 H2 + O2 = 2 H2O
January 21, 2016

Algebra
Nevermind guys, I solved it. For future strugglers: equation A: 3a+12s=262.5 equation B: 4a+8s=230 multiply equation B so that a variable can be negated when you add the two equations together. In this case I chose variable (S) so i multiplied equation B by -1.5 so that -3a=-...
January 19, 2016

Algebra
Math club purchased 3 adult tickets and 12 student tickets for \$262.50. Physics club purchased 4 adult tickets and 8 student tickets for \$230.00. How much do the adult and student tickets cost?
January 19, 2016

Maths
The nth term and the sum of n terms of a geometric sequence are 5 and 55 respectively. If the commom ratio is -(1/2)n find the first term and value of n
January 13, 2016

Math
If a person throws 3 darts at a dartboard, how many possible combinations are there to get a sum of 34?
January 5, 2016

Physics
A baseball player hits a home run over the left-field fence, which is 104 m from home plate. The ball is hit at a point 1.08 m directly above home plate, with an initial velocity directed 35.0° above the horizontal. By what distance does the baseball clear the 3.00 m high ...
December 8, 2015

US History
probaly england
December 2, 2015

math
how much dose 1 cup of sugar cost?
December 2, 2015

Chemestry
Iron metal reacts with oxygen gas to form rust, iron (III) oxide. Which of the following correctly shows the balanced equation for this reaction?
December 2, 2015

math help pls pls
December 2, 2015

Calculus
The amount remaining of a radioactive substance after t hours is given by A(t) = 100ekt. After 12 hours, the initial amount has decreased by 4%. How much remains after 48 hours? What is the half-life of the substance?
November 23, 2015

Physics
Damon, Where do you suggest I look for an approximate mph figure. I realize we are ignoring key factors, but surely someone can give me an educated guess - - e.g. the body would hit the ground at 100 mph plus or minus 10 mph. Thanks
November 20, 2015

Physics
A 180 pound body is dropped from a helicopter 5 miles (26400 ft.) up - - what maximum speed would the body attain, in miles per hour, before hitting the ground? Disregard gravity, air density, etc. factors, a very rough approximation is all that is needed. Thanks.
November 20, 2015

Physics
If a 180 pound body is dropped from an airplane 5 miles (26400 ft.) up: a/ how long would it take for the body to reach the ground? b/ what would be the maximum speed the body would attain in miles per hour? Close approximations are all that are required here. Thanks.
November 20, 2015

Physics
If a 180 pound body was dropped from a plane 5 miles in the air - how long would it take for the body to reach the ground?
November 19, 2015

math
Independent random samples, each containing 800 observations, were selected from two binomial populations. The samples from populations 1 and 2 produced 320 and 400 successes, respectively. Construct a 90% confidence interval for the true difference in population proportions ...
November 18, 2015

math
Suppose x has a binomial probability distribution with n = 200 and p = 0.60. Use the normal approximation to the binomial to find P (X > 130).
November 18, 2015

Physics
The instruments attached to a balloon have a mass of 5kg. The balloon is released and exerts an upward force of 100 N. After the balloon has accelerated for 10s, the instruments are released. What is the velocity of the instruments at the moment of release?
November 2, 2015

Physics
The driver of a car is going 90 km/hr suddenly sees a barrier40m ahead. It takes the driver .75 sec to apply the brakes, and the average acceleration during braking is -10m/s^2. Will the car hit the barrier and use calculation to show work.
October 31, 2015

Physics
10.234234
October 29, 2015

Trig
mercury rotates around the sun in approx. 89 earth days (or 7,689,600 s. use a calculator to approximate its angular speed. choices: 4.09x10^-7 0.035 0.071 8.17x10^-7
October 21, 2015

Did you read The Pig Man And Me
John Quinn does not explain the rule about the paddle to Paul, the narrator of “The Pigman & Me.” How does this one action affect the rest of the essay?
October 11, 2015

HELP SCIENCE ASAP
How are fish, amphibians, reptiles, and birds alike? How are they different? Include at least two similarities and two differences.
October 7, 2015

ela
Which section of a personal narrative requires the most development? a. introduction b. conclusion c. character introduction d. plot my answer is a can you check it for me
October 5, 2015

ELA HELP FAST
Which section of a personal narrative requires the most development? a. introduction b. conclusion c. character introduction d. plot
October 5, 2015

Social Studies
what do you mean
October 5, 2015

Social Studies
What examples are given of a limited government and an unlimited government in the section? How did each type of government affect its citizens? Japans government
October 5, 2015

History
Its fine i got my dad to help me. Thank you
September 13, 2015

History
"The renewable energies roadmap unveiled earlier this month by the Commission sets a target of 20% for the share of total energy supply to come from renewable sources. “It is not the first time that targets for renewable energy have been fixed. In 1997, the European ...
September 13, 2015

psychology
Dr. Jefferson is conducting an experiment in which she is interested in the effects of caffeine on visuospatial ability in adult participants. She conducts an experiment in which she gives one group a pill containing 20mg of caffeine and a second group a placebo pill. One hour...
September 13, 2015

Psychology
A researcher has conducted an experiment in which she has given participants a placebo, 10mg, and 20mg of a drug. She then measured their anxiety, blood pressure, and heart rate in response to the drug. How many levels does this experiment’s independent variable have?
September 13, 2015

Psy 326
We use _______________ to communicate the patterns and distribution of our measured variables.
August 24, 2015

physics
A bird watcher meanders through the woods, walking 0.744 km due east, 0.925 km due south, and 3.97 km in a direction 18.3 ° north of west. The time required for this trip is 1.765 h. Determine the magnitudes of the bird watcher's (a) displacement and (b) average ...
August 14, 2015

Physics
Knowing that you have the mass of each sun, M1=M2=M which is 2x10^30 kg, and you have the distance between the two stars a=1 AU, you can use Kepler's third law to solve for the period in seconds: p^2=((4pi)^2(a)^3)/(Gm) where p is measured in seconds, a is measured in ...
August 14, 2015

physics
A bird watcher meanders through the woods, walking 0.544 km due east, 0.925 km due south, and 3.58 km in a direction 17.3 ° north of west. The time required for this trip is 1.957 h. Determine the magnitudes of the bird watcher's (a) displacement and (b) average velocity.
August 12, 2015

The novel to kill a mockingbird feature a main character named scout. Scout is also the voice that tells the story. What point of view is used in the novel? A.First Person B.Third-Person Limited<----------- C.Third-Person Omniscient The prefix a- can mean "none" ...
August 11, 2015

Math
A ball is thrown, and its height is recorded a number of different times. The ball reaches a maximum height of 20 m after 1.5 s. How do you sketch this relation from just a vertex. Grade 11 functions
July 18, 2015

Math- algebra
An experiment stain of bacteria is being used to treat an oil spill. A colony of 2^13 cells will be sufficient to ocean up the spill. If the colony is started with a single cell, and cells increase in number by splitting every 15 minutes, in how many hours will the colony ...
June 5, 2015

Algebra 2
An object is moving at a speed of 3 + 2 𝑓𝑡/𝑠. How long would it take the object to travel 20 𝑓𝑡? [looking for actual solution and not decimal approximation]
May 1, 2015

Chemistry physics
3.25x10-3 kg of gold is deposited onto the negative electrode of an electrolytic cell in a period of 2.78 hours, what is the current through this cell in amperes? Assume that the gold ions carry one elementary unit of charge
March 31, 2015

Physics
If 3.25x10-3 kg of gold is deposited onto the negative electrode of an electrolytic cell in a period of 2.78 hours, what is the current through this cell in amperes? Assume that the gold ions carry one elementary unit of charge
March 31, 2015

Math
Would it be 122?
March 15, 2015

Math
If the standard error of measurement is 3, and a person scores 125, Standard error of measurement with one standard deviation would put the score at ____?
March 15, 2015

math
A rectangular piece of carpet is place on the floor of a rectangular room leaving a margin of 1 m around it. If the room measures 8 m by 6 m find the area of the room not covered by the carpet.
March 10, 2015

Physics
Carl hits a 0.05 kg golf ball giving it a speed of 65 m/s. What impulse does he impact to the ball?
March 6, 2015

Calculus (Partial Derivatives)
A car dealer determines that if gasoline-electric hybrid automobiles are sold for x dollars apiece and the price of gasoline is y cents per gallon, then approximately H hybrid cars will be sold each year, where H(x,y)=6000−13x^(1/2)+2(0.1y+20)^(3/2). She estimates that t...
March 4, 2015

Calculus (Partial Derivatives)
A car dealer determines that if gasoline-electric hybrid automobiles are sold for x dollars apiece and the price of gasoline is y cents per gallon, then approximately H hybrid cars will be sold each year, where H(x,y)=6000−13x^(1/2)+2(0.1y+20)^(3/2). She estimates that ...
February 28, 2015

Calculus (Partial Derivatives)
It's supposed to be Q(x,y)=40xy^(1/5)
February 28, 2015

Calculus (Partial Derivatives)
Using x hours of skilled labor and y hours of unskilled labor, a manufacturer can produce Q(x,y)=40xy1/5 units each week. Currently 20 hours of skilled labor and 243 hours of unskilled labor are being used. Suppose the manufacturer reduces the skilled labor level by 2 hours ...
February 28, 2015

Economics
1. How does the current anti-corruption movement in China affect relatively tax free countries(ex. monocao, switerland etc.)? 2. EU relation with China
February 26, 2015

physics
Two horizontal forces, and , are acting on a box, but only is shown in the drawing. can point either to the right or to the left. The box moves only along the x axis. There is no friction between the box and the surface. Suppose that = +8.3 N and the mass of the box is 4.5 kg...
February 19, 2015

Calculus
Since it's compunded continuously, you use Present Value = Integrate from 0-T f(t)e^(-rt). It doesn't give a time limit, so we'll assume it's infinte. Integrate from 0-Infinity 110e^(-.08t) =[-1375e^-.08(Inifinity)]-[-135e^-.08(0)] = 0-(-1375) = 1375
February 13, 2015

Chemistry
calculate the density of NH3 at S650mm of Hg
February 11, 2015

Bobpursley
Look at my problem again please thanks
February 5, 2015

Physics
The spring force should be 588 N/m and velocity 0.700 m/s
February 5, 2015

Physics
3 kg object is fastened to a light spring with the intervening cord passing over a pulley. The pulley is frictionless and it's inertia may been neglected. The object is released from rest when the spring is unstretched. If the object drops 10 cm before stopping find the ...
February 5, 2015

physics
January 20, 2015

physics
You set your stationary bike on a high 80 N friction like resistive force and cycle for 30 min at speed of 8 m/s. Your body is 10% efficient at converting chemical energy in your body into mechanical work. What is your internal chemical energy change? How long must you bike to...
January 20, 2015

physics
A fire engine must lift 30 kg of water a vertical distance of 20 m each second. What is the amount of power needed for the water pump for this fire hose? P=W/t=Fd/t=mgd/t (30)(9.8)(20)/1= 5880 W is that right?
January 20, 2015

physics
A 75 kg bobsled is pushed along a horizontal surface by two athletes. After the bobsled is pushed a distance of 4.5 m starting from an initial speed of 1.2 m/s, its speed is 6.0 m/s. What is the change in kinetic energy? Find the magnitude of the net force on the bobsled.
December 15, 2014

physics
A student wearing frictionless in-line skates on a horizontal surface is pushed, from rest, by a friend with a constant force of 45 N. How far must the student be pushed, starting from rest, so that her final kinetic energy is 352 J?
December 15, 2014

physics
How much work is required to accelerate a 0.145 kg baseball from rest, to a speed of 38.7 m/s?
December 15, 2014

Calculus
December 7, 2014

Calculus
Find the area of the region bounded by the curves y=12-x^2 and y=x^2-6. Hint:The answer should be a whole number.
December 7, 2014

Chemistry (Titrations)
In order to standardize a KMnO4 solution, 0.2848 g Fe(NH4)2(SO4)2·6H2O was dissolved in 25 mL 0.18 M H2SO4. The KMnO4 solution was added to the Fe(NH4)2(SO4)2·6H2O solution until a pale pink color persisted. The titration took 24.2 mL of KMnO4 solution. What is ...
November 30, 2014

10.55 Consider an experiment with four groups, with eight values in each. For the ANOVA summary table below, fill in all the missing results: Source Degrees of Freedom Sum of Squares Mean Square (Variance) F Among groups c - 1 = ? SSA = ? MSA = 80 FSTAT = ? Within groups n - c...
November 27, 2014

Math
how to write 4(x+2)+3x+2(x-y) in the distribt. property form
November 23, 2014

Chemistry
Calculate the pH of a 1.19M sodium formate, HCOONa, solution.
November 23, 2014

Chemistry
Calculate the pH of a buffer solution made by mixing 231 mL of a 1.04M trimethylamine (CH3)3N solution with 176 mL of a 1.38M trimethylammonia chloride, (CH3)3NHCl solution. Enter your answer to TWO decimal places. DO NOT use scientific notation.
November 23, 2014

Chemistry
How many grams of nitric acid (HNO3) must be dissolved in 590 ml of water to make a solution with a pOH = 10.1? Select one: a. 2.9 x 10-9 g b. 7.9 x 10-3 g c. 4.7 x 10-3 g d. 7.9 x 10-6 g e. 7.4 x 10-5 g
November 23, 2014

physics
A bee flies to a flower 583 m due south of its hive. The bee’s speed in still air is 0.68 m/s, and there is a wind blowing toward the south at 0.16 m/s. How long will it take the bee to travel to the flower and back to the hive? Answer in units of s
November 18, 2014

Chemistry (Acid&Base)
How many mL of 0.203 M HCl(aq) are required to prepare a diluted solution that has a concentration of 0.0433 M in a 100-mL volumetric flask?
November 16, 2014

Chemistry
Consider the reaction 2 SO2(g) + O2(g) in equilibrium with 2 SO3(g) . At 25°C delta H° = -197.78 kJ and delta S° = -187.95 J/K. Using this information, calculate the equilibrium constant for the reaction at -32°C. (R = 8.314 J/K) Enter your answer using TWO ...
November 16, 2014

statistics
It seems that people are choosing or finding it necessary to work later in life. Random samples of 200 men and 200 women age 65 or older were selected, and 80 men and 59 women were found to be working. At á = 0.01, can it be concluded that the proportions are different
November 15, 2014

Statistics
Suppose that the probability that a new medication will cause a bad side effect is 0.03. If this medication is given to 150 people, what is the probability that more than three of them will experience a bad side effect?
November 14, 2014

physics
Rubber tires and wet blacktop have a coefficient of kinetic friction of 0.5. A pickup truck with a mass 750 kg traveling 30.0 m/s skids to a stop. (a) what is the size and direction of the frictional force that the road exerts on the truck? (b) Find the acceleration of the ...
November 11, 2014

calculus related rates
Boyle’s law for the expansion of a gas is PV = k, where P is the pressure (in pounds per unit of area), V is the volume of the gas, and k is a constant. Find the expression that shows the rate of change of the pressure as related to the rate of change of the volume. dP/...
November 11, 2014

Physics
A dog sled weighing 750 lb is pulled over level snow at a uniform speed by a dog team exerting a force of 60 lb. find the coefficient of friction.
November 11, 2014

physics
A plane cruising at 247 m/s accelerates at 28 m/s 2 for 8.7 s.How far will it have traveled in that time?
October 22, 2014

physics
A car travels in a straight line for 2.8 h at a constant speed of 53 km/h . What is its acceleration? Answer in units of m/s 2
October 21, 2014

physics
Water is poured into a container that has a leak.The mass 'm' of the water is given as a function of time 't' by, m=5t^0.8 -3t + 20 , with t>=0, mass in grams and t in seconds A) at what time is the water mass greatest,and B) what is the greatest mass? In ...
October 19, 2014

Physics
The space shuttle, with an initial mass M = 2.41×106 kg, is launched from the surface of the earth with an initial net acceleration a = 26.1 m/s^2. The rate of fuel consumption is R = 6.90×103 kg/s. The shuttle reaches outer space with a velocity of vo = 4632. m/s...
October 13, 2014

physics
A space probe is to be put into a circular orbit of radius 42.00 km about an asteroid. At this radius the magnitude of the gravitational acceleration, normally referred to as the "gravitational field", is 1.00×10-3 meters per second squared. What speed, in ...
October 13, 2014

help
If BaSO4 ppt is isn't washed or dried adequately how will this effect the sulfate percent error determination?
October 12, 2014

Chem lab
Student Calamity reported a final yield of 50%. List four things she might have done wrong to account for this yield. Student Overachiever reported a final yield of 115%. List two things he might have done wrong to account for this yield.
October 11, 2014

chemistry
you have not added enough sodium hydroxide to precipitate all the copper as copper hydroxide. How could you tell that not all the copper had precipitated?
October 11, 2014

physics
A mass m = 6.0 kg is attached to the lower end of a massless string of length L = 27.0 cm. The upper end of the string is held fixed. Suppose that the mass moves in a circle at constant speed, and that the string makes an angle theta = 28° with the vertical, as shown in ...
October 7, 2014

statistics
There are two companies that sell the medication, Company A and Company B. Company A’s tablets have a mean of 5 mg of medication and Company B’s tablets also have a mean amount of 5 mg of medication. This information would lead you to believe that it would make no ...
September 28, 2014

Math
Find the locus of points that satisfy (a) |z+1| = |z+i| (b) Re z = |z-1| and sketch them in the complex plane.
September 22, 2014

AP Alegebra
simplify (sqrt(x)+1)/(sqrt(x)-1)
September 7, 2014

Physics
just submitted the answer... to two sig figs it would be 53000 or 5.3x10^4
August 27, 2014

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