Friday
December 2, 2016

# Posts by Don

Total # Posts: 573

Maths
How many ordered triples of positive integers (a,b,c) with 1<=a,b,c<=5 are there such that ax^2+bx+c has a rational solution?
March 1, 2013

maths
How many ordered triples of positive integers (a,b,c) with 1¡Üa,b,c¡Ü5 are there such that ax^2+bx+c has a rational solution?
February 28, 2013

Probabilities
A queen on an English chessboard is able to attack in the same row, column and diagonal. The probability that 2 randomly placed queens on an 8 by 8 chessboard will be able to attack each other can be expressed as a/b , where a and b are positive, coprime integers. What is the ...
February 28, 2013

Physics
The coil of wire in a galvanometer has a resistance of RC = 78.0 Ù. The galvanometer exhibits a full-scale deflection when the current through it is 0.440 mA. A resistor is connected in series with this combination so as to produce a voltmeter. The voltmeter is to have ...
February 24, 2013

Physics
In the drawing below, R1 has a resistance of 6.2 Ù and R2 has a resistance of 2.6-Ù. Determine the current (magnitude and direction) in the 6.2 and 2.6-Ù resistors in the drawing.
February 24, 2013

Physics
A battery has an internal resistance of 0.017 Ù and an emf of 9.00 V. What is the maximum current that can be drawn from the battery without the terminal voltage dropping below 8.75 V?
February 23, 2013

math
How much money would have to be deposited into a compound interest savings account earning 5% each year in order to accumulate \$10,000 in 18 years?
February 23, 2013

trig
To determine the distance to an oil platform in the Pacific Ocean, from both ends of a beach, a surveyor measures the angle to the platform from each end of the beach. The angle made with the shoreline from one end of the beach is 83 degrees, from the other end 78.6 degrees. ...
February 19, 2013

calculus
I need help with this problem: The path traveled by a golf ball with a 9-iron can be modeled with the quadratic equation, y= -0.042xsquared + 5x, where x is the distance in yards from the point it was hit and y is the height of the golf ball in feet. Assume that the ground is ...
February 19, 2013

Physics
The electric potential energy stored in the capacitor of a defibrillator is 77 J, and the capacitance is 123 µF. What is the potential difference that exists across the capacitor plates?
February 18, 2013

14)c 15)b 16)d 17)c 18)b
February 14, 2013

3) pienso 4)entiende 5)prefieren 6)quieres 7)pensamos 8)cierre 9)cerramos 10)digo 11)dice 12)decimos 13)dicen
February 14, 2013

Spanish
1) a 2)c
February 14, 2013

mathURGENT!!!!!!!!!!
find all ordered pairs of positive integers (x,y) that satisfy the following equation: x^y=2^64. please answer and explain how you got it!!!!
February 14, 2013

mathURGENT!!!!!!
the lines satisfying the equations x+2y=3 and 3y+ax=2 are perpendicular to each other. find the value of 'a'. please answer and explain how you got, please!!
February 5, 2013

mathURGENT!!!!!!
determine the smallest prime number that divides the following sum: 3^12+5^13+7^14+11^15? please answer and explain step by step how u got it!!!!
February 4, 2013

Physics
The drawings show three charges that have the same magnitude but different signs. In all cases the distance d between the charges is the same. The magnitude of the charges is |q|= 5.5 µC, and the distance between them is d = 4.3 mm. Determine the magnitude of the net ...
February 3, 2013

Physics
Two tiny conducting spheres are identical and carry charges of -19.8 µC and +54.5 µC. They are separated by a distance of 2.45 cm. (a) What is the magnitude of the force that each sphere experiences, and is the force attractive or repulsive? 1 N 2 ---Select--- ...
January 29, 2013

mathURGENT!!!!!!!
a certain type of candy is sold in small boxes of 8 and large boxes of 15. notice it would be impossible to buy exactly 12 candies without breaking up a box. it would also be impossible to buy 17 candies without breaking up a box. what is the greatest number of candies that it...
January 26, 2013

math URGENT!!!!!!!
a certain type of candy is sold in small boxes of 8 and large boxes of 15. notice it would be impossible to buy exactly 12 candies without breaking up a box. it would also be impossible to buy 17 candies without breaking up a box. what is the greatest number of candies that it...
January 22, 2013

MATH URGENT!!!!!!!
the will of an eccentric millionaire reads as follows: "i leave 4/17 of my estate to my son, 7/13 of the remainder to my wife, 2/3 of this remainder to my daughter, and the remaining \$2million to my dog." what was the total amount of the estate? please answer and ...
January 19, 2013

CHEMISTRY
An equilibrium mixture of the following reaction was found to have = 0.0325 at 1200 degrees C. What is the concentration of I? I2(g)<->2I (g) Keq=1.3×10−2 at 1200
November 28, 2012

chem 4
How many grams of sodium chloride are needed to make 1 L of 0.9% (m/v) sodium chloride solution (“isotonic saline”).
November 22, 2012

chem 3
(a) If H is positive and S is negative, would G to be positive or negative or is it dependent on T? (b) For the sign of G that you have in part (a) would the reaction be spontaneous, nonspontaneous, or dependent on the value of T?
November 22, 2012

chem 2
What is the concentration of the final solution if 1 liter of 6 M HCl is diluted to a final volume of 2 L?
November 22, 2012

chem 1
if 58.44 g of sodium chloride is dissolved in 0.5 liter of water what is the molarity of the sodium chloride solution? The molar mass of sodium chloride is 58.44 grams per mole.
November 22, 2012

chem
2 NO(g) + O2(g) 2 NO2(g) For the reaction above tell whether the reaction would shift to the left (L) or right ® if I a. Increased the total pressure of the system b. Removed O2 from the system c. Increased the amount of NO in the system
November 22, 2012

Physics
A 0.069-kg arrow is fired horizontally. The bowstring exerts an average force of 65 N on the arrow over a distance of 0.95 m. With what speed does the arrow leave the bow?
November 12, 2012

Physics
A cable lifts a 1060-kg elevator at a constant velocity for a distance of 39 m. What is the work done by each of the following?
November 12, 2012

Physics
A student (m = 63 kg) falls freely from rest and strikes the ground. During the collision with the ground, he comes to rest in a time of 0.0120 s. The average force exerted on him by the ground is +17000. N, where the upward direction is taken to be the positive direction. ...
November 12, 2012

Physics
Suppose the surface (radius = r) of the space station in the figure is rotating at 38.6 m/s. What must be the value of r for the astronauts to weigh one-half of their earth-weight?
November 7, 2012

Physics
Two banked curves have the same radius. Curve A is banked at an angle of 11°, and curve B is banked at an angle of 16°. A car can travel around curve A without relying on friction at a speed of 18.5 m/s. At what speed can this car travel around curve B without relying ...
November 7, 2012

Physics
A "swing" ride at a carnival consists of chairs that are swung in a circle by 12.0 m cables attached to a vertical rotating pole, as the drawing shows. (è = 60.0°) Suppose the total mass of a chair and its occupant is 222 kg
November 7, 2012

physics
Each of the space shuttle's main engines is fed liquid hydrogen by a high-pressure pump. Turbine blades inside the pump rotate at 595 rev/s. A point on one of the blades traces out a circle with a radius of 0.02 m as the blade rotates. (a) What is the magnitude of the ...
November 7, 2012

physics
A satellite is in a circular orbit about the earth (ME = 5.98 1024 kg). The period of the satellite is 4.20 104 s. What is the speed at which the satellite travels?
November 7, 2012

Physics
A racetrack has the shape of an inverted cone, as the drawing shows. On this surface the cars race in circles that are parallel to the ground, and the surface is at an angle è = 20°. For a speed of 40 m/s, at what value of the distance d should a driver locate his ...
November 7, 2012

Physics
Two banked curves have the same radius. Curve A is banked at an angle of 11°, and curve B is banked at an angle of 16°. A car can travel around curve A without relying on friction at a speed of 18.5 m/s. At what speed can this car travel around curve B without relying ...
November 7, 2012

Physics
A block is hung by a string from the inside roof of a van. When the van goes straight ahead at a speed of 31 m/s, the block hangs vertically down. But when the van maintains this same speed around an unbanked curve (radius = 145 m), the block swings toward the outside of the ...
November 7, 2012

Physics
A stone has a mass of 6.00 10-3 kg and is wedged into the tread of an automobile tire, as the drawing shows. The coefficient of static friction between the stone and each side of the tread channel is 0.73. When the tire surface is rotating at a maximum speed of 17 m/s, the ...
November 7, 2012

Physics
The earth rotates once per day about an axis passing through the north and south poles, an axis that is perpendicular to the plane of the equator. Assuming the earth is a sphere with a radius of 6.38 106 m, determine the speed and centripetal acceleration of a person situated ...
November 6, 2012

Physics
The earth rotates once per day about an axis passing through the north and south poles, an axis that is perpendicular to the plane of the equator. Assuming the earth is a sphere with a radius of 6.38 106 m, determine the speed and centripetal acceleration of a person situated ...
November 6, 2012

chem
What is the total pressure of a mixture of 0.3 atm of F2, 0.5 atm of Cl2, and 0.8 atm of O2?
November 5, 2012

chem
Calculate the number of mol of helium in a 11.2 L balloon at 300 K and 1.00 atm of pressure ?
November 5, 2012

chem
If 10.0 mol of CO occupies a volume of 20.0 L what volume would 4.0 mol of CO occupy?
November 5, 2012

Physics
During a storm, a tree limb breaks off and comes to rest across a barbed wire fence at a point that is not in the middle between two fence posts. The limb exerts a downward force of 148 N on the wire. The left section of the wire makes an angle of 12° relative to the ...
October 30, 2012

Physics
The drawing shows three particles far away from any other objects and located on a straight line. The masses of these particles are mA = 363 kg, mB = 517 kg, and mC = 154 kg. Find the magnitude and direction of the net gravitational force acting on each of the three particles...
October 30, 2012

math
7x9=63
October 16, 2012

enviromental
Completely mixed flow ractor CSTR and plug flow reactor (PFR) may have significantly different efficiencies depending on the reaction order. This problem asks you to compare the relative reactor sizes required to ensure 99.0 % removal of wastewatwer pathogens. Wastewater from ...
October 14, 2012

math
October 9, 2012

Phy I
Two forces, 1 and 2, act on the 5.00 kg block shown in the drawing. The magnitudes of the forces are F1 = 47.5 N and F2 = 34.5 N. What is the horizontal acceleration (magnitude and direction) of the block?
October 3, 2012

Math
Suppose an odd function f has an inverse g. Prove that g is also odd.
September 26, 2012

Math
What is 6 less than half a number?
September 23, 2012

geometry
if AB=CD, AB is 12-y, CD = 3x-4y, BD = 18, AC = x+y, what is x, y, and AC
September 15, 2012

calculus
I need help with the following problem: From a point 50 meters from the bottom of a radio tower along level ground, the angle of elevation to the top of the tower is 67 degrees. What is the height of the tower?
September 3, 2012

Calculus
I need help with the following problem: You're in a hot air balloon with your support crew on the ground. Attached to the balloon are two tether cords of length 350 feet and 400 feet that your crew attached to the ground. These cords form an angle of 50 degrees where they ...
September 3, 2012

calculus
I need help with the following question: Which of the following is an example of a function whose derivative is always 3? Choices are: f(x) = x=3 f(x) = 5x+3 f (x) = 3x+5 f(x) = 3 Thank you.
August 28, 2012

math
I need help answering the following question: A road sign reads: "5% grade next 4 miles." What is the change in elevation from the lookout to the point four miles ahead (to the nearest foot)?
August 26, 2012

math
I need help with the following question: While fishing on a lake, you see a fish below water at a 25 degree angle with the surface, producing air bubbles on the surface of the water 20 feet ahead. How far away is the fish from the boat?
August 26, 2012

Calculus
Sorry - the total amount of fencing is 240 feet
August 24, 2012

Calculus
How do I find the total area of three connected equally sized pens built so as to maximize the area bounded?
August 24, 2012

math
out of 40 people,17 have brothers,22 have sisters and 9 have both.how many people have neither brothers nor sisters
August 18, 2012

math
sue has some ducks and some goats,if there are 36 legs altogether,what is the greatest number of goats possible
August 18, 2012

math
a number of teachers were to receive 6 pens each ,but needed 4 more pens for them to be equally divided.if each teacher received 9 pens, 25 more pens would be necessary.how many pens are there
August 18, 2012

math
my average results from the last 4 maths exams was 18 out of 25.what mark do i need in my fifth exam in order to increase the everage by 3%
August 18, 2012

math
a cube made up of some blocks and there are 12 cubes ,block a and b are removed from each other.how many blocks will remain in the 12 cubes altogether
August 18, 2012

math
a pool is filled with water in 6 hours at 100 m every hour. If 125 m could be filled every hour,the pool would be full at 11.00am.What was the latest possible time that the water could have started filling the pool
August 11, 2012

math
a large cogwheel contains 117 cogs, and a small one contains 52 cogs.if the large wheel revolves 20 times,find the amount of revolutions of the small wheel.
August 11, 2012

math
what is the next number of 3,4,8,17,33
August 11, 2012

math
a triangle,side ac is 3/5 of side ab,and is 23.1 m. side ab is 7/9 of side bc.angle b is 1.5 times larger than angle c,and angle a is twice the size of angle c.how many degrees is angle A
August 11, 2012

math
oout of 45 people ,37 caught the train,15 the bus,5 walked.how many caught both bus and train?
August 11, 2012

math
28 students,all of whom study either science,language or both.18 students study language and 14 study science.how many students study acience and language? and how many study only science?
August 11, 2012

math
there are 28 students,all of whom study either science,language or both,18 students study language and 14 study science.How many students study science and language?
August 11, 2012

math
6 builders worked 8 hours a day for 10 days to complete a job.If 8 builders worked 6 hours a day for 3 days,the remaining work has to be completed by 6 builders in 8 days.How many hours does each builder need to work each day?
August 11, 2012

math
6 builders worked 8 hours a day for 10 days to complete a job.If 8 builders worked 6 hours a day for 3 days,the remaining work has to be completed by 6 builders in 8 days.How many hours does each builder need to work each day?
August 11, 2012

math
how many grams are there in 1 km
August 5, 2012

math
3trucks are equal in weight to 2 trucks and 2 sedans.What fraction of the weight of a truck is the weight of a sedan
August 5, 2012

math
front wheels of a cart have a circumference of 3 metres.back wheels have a circumference of 4 metres.A white dot is painted on the rim of each wheel it touches the ground.the cart is then driven 100 metres.including the starting position,how many times will the white dots be ...
August 4, 2012

math
121 balls are placed in group of 7and 5 in basket.how many baskets 0f 7 were there?
July 29, 2012

math
how many words of 1;2;3 letters can be made from the letters in CART
July 21, 2012

math
the day is 1hour 18minutes longer than the night.how long is the day?
July 5, 2012

COM200: Interpersonal Communication
self concept can be changed through interpereosnal communiciation
June 21, 2012

math
how to write 9.035 in expanded notation
June 17, 2012

math
complete these series,1,8,27,64,___,____
June 17, 2012

math
complete these series,1,8,27,64,___,____
June 17, 2012

math
twin primes have one composite number between them(e.g.5,7).write one pair of twin primes between number 20 and 40
June 9, 2012

math
label its dimensions after you rule a square the same area as this rectangle on the back of this sheet 16mm ,4mm
June 9, 2012

math
1/5 of 35 +16 equal?
June 9, 2012

math
how many times greater is the first 7 than second in 876574?
June 9, 2012

math
there are 3 shirts,2 caps,4 pairs of shorts.how many different outfits can wear ?(consisiting of one shirt,one pair of shorts and one cap
June 9, 2012

math
howmany degrees does a person turn who was facing north and now faces south?
June 9, 2012

math
there are 23 of? in 2.3
June 3, 2012

math
what is different between a decimal and a decimal point?
June 3, 2012

math
.in the decimal fractions0.1 and 0.02 the numeral 1 is ?
June 2, 2012

math
what fraction of 6cm is 15mm .
June 2, 2012

math
express64in3 different ways,using only index notation
June 2, 2012

Physics
An electric immersion heater is rated 5 A when connected to a 120V circuit. What is the resistance of the heater? If it takes 168 KJ to heat 500 ml of water from 20 deg C to boiling, how long does it take to heat the water?
May 18, 2012

Physics
Ahhh so its 120*7.5*50seconds 7.5 being the amps that the drill draws and 50 being the time and 120 being the voltage.
May 18, 2012

Physics
Hi bob, could you explain how you came to that calculation, please. As in where did the 1.5 come from, and the 50 joules(it was 50 seconds) I'm lost, could you help? Thanks
May 18, 2012

Physics
An electric drill operates at a potential difference of 120V and draws a current of 1.5 Amps. If it takes 50 seconds to drill a hole in a piece of steel,calculate the amount of electrical energy used by the drill in that time.
May 18, 2012

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