Wednesday
November 26, 2014

Posts by Don


Total # Posts: 528

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
Holy Waa!! Your dad is a loan shark.... call the cops!
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

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

Computer
I have open office and can't find the symbols tab.. arghh
May 18, 2012

Computer
Hi Ms. Sue ... how do you make the small 3 by itself after the 10?
May 18, 2012

Computer
On a laptop, how do you get the 10 to the 3rd power? ( make a small 3 after the 10?)
May 18, 2012

physics
a 12 Volt car battery supplies 1.0 x 10^3 C of charge to the starter. How much energy is used to start the car? ( it's not 10 cubed, but 10 to the third power)
May 18, 2012

physics 30
an object is thrown from 1.5m above the ground with a velocity of 15m/s and at an angle of 25deg with the ground. using vectors and motion equations, determine how long the object will remain in the air before returning to the ground. ARGHHHHHH help please..
May 13, 2012

Physics
a 70g bag of potato chips contains 1.6MJ of energy. Working at your maximum power, how long would it take to burn this energy?
May 6, 2012

Physics
If I know the length of all 3 sides in a right angle triangle, how do I get the degrees of the other angles? Which formula do I use again?
May 6, 2012

Physics 30
a 2000kg car traveling east at 24m/sec enters an icy (frictionless) intersection and collides with a 3600kg truck traveling south at 10 m/sec. If they become coupled together in the collision, what is their velocity immediately after impact?
May 1, 2012

math
there are 3 arrays for 4, how many arrays can be drawn for each prime numbers
April 29, 2012

math
there are 122 houses,how many times does the digit 2 appear on the letterboxes?
April 29, 2012

maath
there are 3 arrays for 4.how many arrays can be drawn for each prime numbers
April 29, 2012

Physics 30
If a truck moving at 30km/hr accelerates at 2.5m/s^2 to 50 km/hr, what time (in sec) does it take? a. 2.22s b. 5.56s c. 8 s d. 28.8s
April 20, 2012

algebra
if the red river is 500 miles longer than the blue river. if the sum of their lengths is 5550 miles what is the length of each river
April 16, 2012

algebra
Can someone help me figure this out please? when you solve a system of equations by the substitution method, how do you determine whether the system of equations is inconsistent? thank you anyone
March 18, 2012

algebra
I need help. Can someone help me please. Explain how you can determine from the graph of a system of two linear equations in two variables whether it is an inconsistent system of equations. Thank you
March 18, 2012

Physics
(.50 kg )(35.7m/s^2) = ? kilograms meters per second squared
March 17, 2012

calc
by applying rolle's theorem, check whether it is possible that the function f(x) = x^5 + x -17 has two real roots. your reason is that if f(x) has two real roots then by rolle's theorem, f'(x) must be equal to what at certain value of x between these two roots, but...
March 16, 2012

chemistry
Carbon monoxide gas and hydrogen gas are mixed in a two liter flask. The reaction produces methanol gas as the only product. At equilibrium the Keq is 1.1 x 10-5. The flask initially held 6 grams of hydrogen and the equilibrium concentration of hydrogen is 0.1 M. How many ...
March 12, 2012

Discete Math
Show that there must be at least 90 ways to choose six integers from 1 to 15 so that all choices have the same sum.
February 27, 2012

Physics 30
First A(B-A) then subtract B again from that answer. I see A as (0,3.5) and B as (-4.2,0) I hope thats the right way algebraically.
February 21, 2012

Physics 30
Hi Bob ... the first post is actually the question .. subtract B from A(B-A)
February 21, 2012

Physics 30
Vectors A) 3.5 cm North B) 4.2 cm West Algebraically subtract B from A(B-A) Whaaaa? Please help
February 21, 2012

math
a sales representative earned four times as much in the fourth week of jan than any other week in jan what is the income for the fourth week
February 19, 2012

math
If a tree is 10 feet tall after two years and 25 feet tall after 5 years, find the rate of change of growth of the tree if y is the height in feet and x is the number of years. Be sure to give correct units.
February 12, 2012

chemistry
(100g)(.473J/g°C)(x-62°C) =-(500g)(4.184J/g°C)(x-22°C) Q = mass•specific heat•change in temperature Can someone show me how to solve this so i can teach myself before my test on Monday ..thanks for your time
February 3, 2012

Math
Fred runs a lap every 2 minutes and Mark runs a lap every 2.5 minutes. They start together. How long will it be before they are next to each other again?
January 19, 2012

Trig
(x+3)^2/4^2 + (y-2)^2/5^2 The location of the Foci are at: a.(-3,-1) and (-3,-5) b. (-3,2) and (-3,5) c. (-3,-3) and (-3,7) d. (-3,1) and (-3,-5) I get (-3,2) and (-3,5) Am I correct?
January 14, 2012

Trig
The question is: Set up a 2 column proof to show that each of the equations is an identity. Transform the left side to become the right side. a. (tan + cot)^2 = sec^2 + csc^2 I'm having trouble with this. b. (cos + sin)/cos + (cos - sin)/sin = csc sec I'm having ...
January 8, 2012

Trig
Thanks Damon.
January 8, 2012

Trig
The actual question goes : make the left the same as the right: left side: tan/sec - 1 = right side sin/1-cos
January 8, 2012

Trig
(sin/cos)/ ( 1/cos - 1) = I'm stumped
January 8, 2012

Trig
The question says: Set up a 2 column proof to show that each of the following equations is an identity. Transform the left side to become the right side. (tan + cot)^2 = sec^2 + csc^2
January 8, 2012

Trig
Hi Damon .. apparently they want the right side to stay "as is" and for the left side to transform into exactly what the right side says .... sorry
January 8, 2012

Trig
Proving Identities: 2 columns (tan + cot)^2 = sec^2 + csc^2 I'm having trouble breaking down the left side to = the right side.. Any help please
January 8, 2012

Trig
ARGHHHHH now that really was a brain fart on my part ... Thanks a lot Reiny for the help Don
January 4, 2012

Trig
(x+0)^2 + (y+4)^2 = 17 the center would be (0,4) I can't see it any other way ...arghhhh
January 4, 2012

Trig
I'm not sure what your looking for Reiny. It looks like the center of the circle is still (0,4) what am I doing wrong?
January 4, 2012

Trig
the center of a circle x^2 + y^2 + 8y =1 is a. (0,-2) b. (0,4) c. (0,1) d. (0,-4) I believe the answer is (0,4) Am I correct ?
January 4, 2012

Trig
The center of the circle (x+2)^2 + (y-3)^2 =1 is a. (2,3) b. (-2,3) c. (2,-3) d. (-2,-3) I believe b. is the answer, is that correct?
January 4, 2012

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