Friday
December 9, 2016

Posts by Mark

Total # Posts: 1,582

Physics
We have a heat engine that produces 150 J of heat, does 40 J of work, and emits 110 J into another system. What is the efficiency of the heat engine? (show you work)
December 7, 2016

Statistic
Heights of men on a baseball team have a? bell-shaped distribution with a mean of 169 cm169 cm and a standard deviation of 9 cm9 cm. Using the empirical? rule, what is the approximate percentage of the men between the following? values? a. ?% of the men are between 142 cm and ...
December 7, 2016

Physics
How much heat energy is needed to change 0.25kg of water at 100°C to steam at 100°C? Show your work. Please don't give me the answer, I just need help figuring out how to find the answer. Thanks!
December 7, 2016

Math
The bottom 30% of the students failed an end of semester exam. The mean for the test was 130 and the standard deviation was 27. What was the passing score?
December 7, 2016

Physics
How much heat energy is needed to change 0.25kg of water at 100°C to steam at 100°C? Show your work. Please don't give me the answer, I just need help figuring out how to find the answer. Thanks!
December 7, 2016

Trigonometry
All values of theta are positive. From left to right, the first peak occurs at (pi/2,1) and the second peak occurs at (9pi/2). A. Write the graphs equation as a cosine function. B. Write the graphs equation as a sine function.
November 23, 2016

physics
Two forces are applied to a 0.5 kg hockey puck causing it to accelerate. The first force has a magnitude of 10.0 N and is applied to the puck at an angle of 80 degrees with respect to the x axis. The second force has a magnitude of 3.5 N and is applied to the puck at an angle ...
November 22, 2016

Math
Ricky took a survey in the fifth grade and found that 2/3 of the students ride the bus to school and 1/4 of the students walk. What fraction of the fifth grade students either ride the bus or walk to school?
November 21, 2016

Stats
In a large section of a statistics class, the points for the final exam are normally distributed, with a mean of 72 and a standard deviation of 9. Grades are to be assigned according to the following rule: The top 10% receive A's. The next 20% receive B's. The middle ...
November 18, 2016

geometry
Find the measure of each exterior angle of a regular polygon whose central angle measures 120 degrees.
November 15, 2016

geometry
Find the measure of each interior angle of a regular polygon whose central angle measures 60 degrees.
November 15, 2016

Math ?
Yes absolutely. I will try my hardest, afterall the only thing I can do is to try my very best:)
November 10, 2016

Math ?
Alright, thank you so much. I am not happy with my marks at all, but I suppose some professors have high expectations.
November 10, 2016

Math ?
I have a dilemma; my English professor doesn’t give us our grades so I currently don’t know what percent I am at in the class. I really need to know since I need to know if I’ll be passing or not. He doesn’t grade anything with percent’s, and gives us ...
November 10, 2016

English
It is a riddle: We see it every morning, it has very many colours. At one point we all have in our lives Please help me solve this riddle and an explanation of it.
November 8, 2016

Physics
What is the reaction of the earth pulling down on a pen that is lying on a table
November 7, 2016

Help! [Math]
Would it be 2.7/9.0 x 10^1? Which then becomes 2.7/9.0 x 1? Which then becomes 2.7/9.0? So confused.
October 24, 2016

Help! [Math]
2.7/9.0 x 10^(-5)-(-6) = ? I can't figure it out :'c
October 24, 2016

English help
I added more of my ideas: Is the main conflict in Return of the soldier between Chris's desire to return to the past and his responsibility to the present, between Jenny and Kitty or is it between two other opposing forces? I must write an essay about this so please help ...
October 21, 2016

English
Rewrote This because I added more of my ideas: Is the main conflict in Return of the soldier between Chris's desire to return to the past and his responsibility to the present, between Jenny and Kitty or is it between two other opposing forces? I must write an essay about ...
October 20, 2016

English
Is the main conflict in Return of the soldier between Chris's desire to return to the past and his responsibility to the present, between Jenny and Kitty or is it between two other opposing forces? I must write an essay about this so please help me. I do feel its the first...
October 20, 2016

Math -data management
There are 5 rock songs, 6 country songs, and 3 hip-hop songs. How many different albums can be formed using the songs if the album should contain at least 1 rock song and 1 country song? My solution: 14C5x14C6x14C3-5C1x6C1 Is this correct? Thanks in advance
October 13, 2016

american government
what is #8 B or C
September 24, 2016

math
the schematic of a rectangular patio is drawn 1/8 inch to a foot if the patio is 18 feet long what is the measure of the patios length on the schematic
September 23, 2016

physics
an object of height 5cm is placed 20cm in front of a concave mirror of radius of curvature 20cm by graphical method, find image distance from the mirror
September 21, 2016

Math
11^2=11x11=121
September 20, 2016

Math
yes
September 20, 2016

Maths Constructions
You draw segment BC first. Then you use the protractor and mark 60 so you draw line at 60 the same for 75 ,and you connect the lines.
September 20, 2016

science chemistry
H2O+CuS->CuO+2H++2e 4H++SO4^2-=SO2+2H2O
September 20, 2016

math (algebera)
You have 4 unknowns?
September 20, 2016

Chemistry
There have been two ways on making transuranium elements: neutron bombardment and a)beta bombardment b)gamma bombardment c)positron bombardment d)photon bombardment e)heavy atom bombardment
September 18, 2016

geography
Which items are examples of human-environmental interaction? coal mines the interstate highway system meteor showers oil deposits shopping malls
September 8, 2016

Algebra II
A potter is making cups and plates. It takes her 6 minutes to make a cup and 3 minutes to make a plate. Each cup uses 3/4lb. of clay and each plate uses one lb. of clay. She has 20 hours available for making the cups and plates and has 250lbs. of clay on hand. She makes a ...
September 7, 2016

Math
Try writing the question exactly and completely as given to you without interpretation. I don't know what you are looking to find.
September 7, 2016

math
5(x+10) + x can be solved using the distributive property. First multiply the 5 times the x =5x Then multiply the 5 times the 10 = 50 You now have 5x + 50 + x. Combine like terms (5x and x) to arrive at the correct answer of 6x + 50
September 7, 2016

MATH
8
September 5, 2016

Algera check answers
.25 inches per hour
August 31, 2016

English
It is the ugliest but has so many colors
August 30, 2016

geometry
I should clarify how to solve the problem. We start with V = pi r^2 h. Solve for r^2; 63 = pi r^2 5. First divide by pi and then by 5. Get the square root of your answer (4.0107) to get the radius of 2.002674. Next we increase everything by 100% and use a height of 10 and a ...
August 18, 2016

geometry
The volume of the larger beaker would be 504 inches cubed.
August 18, 2016

Math
If a run is 10 feet and the slope 1% what is the rise?
July 13, 2016

Trigonometry
two airplanes leave an airport at the same time one hour later they are 189km/hr apart. if one plane traveled 168km/hr and the other traveled 244km/hr for the hour what is the angle between their flight path
June 8, 2016

Trigonometry
11. If a navigation error puts a plane 2.5° off course, how far off course is the plane after flying for 2 hours at 152 miles per hour?
June 8, 2016

Trigonometry
10. A person notices that the angle of elevation from where he is standing to the top of a pole is 40°. Then he backs up 12 feet and notices that the angle of elevation to the top of the pole is now 32°. How tall is the pole?
June 8, 2016

Trigonometry
9. A boat travels on a course of bearing N37°W for 83 miles. How many miles north and how many miles west has theboat traveled?
June 8, 2016

Trigonometry
prove this identity: secθ +1/tanθ = tanθ/secθ −1
June 8, 2016

Trigonometry
28. Find all solutions if 0° ≤θ <360°. 4sin2 (3θ)−3= 0
June 7, 2016

Trigonometry
27. Solve for all radian solutions. sinx = −2cos x
June 7, 2016

Trigonometry
26. Solve for 0≤ x <2π . 2+3cos x = 2sin2 x −1
June 7, 2016

Trigonometry
24. Let cscθ = 5 with θ ∈QII and find the following. *use double identity a) cosθ b) cotθ
June 7, 2016

Math
2.4 (n - 1)= 12
May 16, 2016

Math
How 12in patio brick will fit a 13ft long 7ft wide space
May 15, 2016

Math
A group consists of 5 boys and 6 girls how many committees of five can be formed that consists of 2 boys and 3 girls?
May 11, 2016

HCC
if x=4 which of the following expression DOES NOT equil 9?
May 11, 2016

Trigonometry
I need help graphing y=csc(x+pi/4) on the interval -pi/2<x<3pi/2
April 28, 2016

Physics! Volume!! HELP
An object hanging on a scale reads 24.0g when submerged in water, but 48.0 g when submerged in oil (specific gravity 0.80) Find the density of the object.
April 27, 2016

Math
The number of bacteria in a certain culture T hours from now grows according to A=800(3)^t what will the count be in 3.12 hours from now?
April 25, 2016

PHYSICS HELP! ROLLING MOTION
The five masses below all have the same radius and a cylindrically symmetric mass distribution. They start to roll down an inclined plane, starting from rest, at the same time and from the same height. Give their order of arrival at the bottom. (a) Icm=935 g*cm2, M = 44g (b) ...
April 25, 2016

PHYSICS! HELIUM BALLON
Under standard conditions, the density of air is 1.293 kg/m3 and that of helium is 0.178 kg/m3. A spherical helium balloon lifts a basket plus cargo of mass 277.0 kg. What must be the minimum diameter of the spherical balloon?
April 25, 2016

my son's math help please
Each week Susie washes dishes three nights,washes clothes one night,empties trash cans two nights,and cook supper one night.If her Aunt Nancy stopped by randomly one night,what are the chances that Susie would be cooking that night!
April 18, 2016

help my son's math
Jamie won the spelling bee.she completed 8 more rounds than Antonio,who completed three times as many rounds as beth.If beth completed 6 rounds, how many rounds did jamie completed?
April 11, 2016

Algebra
Okay, so I got 60/17 = 3.529 hours?
April 7, 2016

Algebra
Sue, an experienced shipping clerk, can fill a certain order in 5 hours. Jim, a new clerk, needs 12 hours to do the same job. Working together, how long will it take them to fill the order?
April 7, 2016

Chemistry
Radium-223 nuclei usually decay by alpha emission. Once in every billion decays, a radium-223 nucleus emits a carbon-14 nucleus. Write a balanced nuclear equation for alpha emission. Write a balanced nuclear equation for carbon-14 emission.
April 7, 2016

Algebra
Thank you Steve.
April 7, 2016

Algebra
I posted the wrong problem for my work provided, although I am struggling to answer both. The correct problem for my work provided is as follows. A car Traveled 132mi at a certain speed. If the speed had been 11mph faster, the trip could have been made in 2hr less time. Find ...
April 7, 2016

Algebra
Person A can paint the neighbor's house 2 times as fast as Person B. The year A and B worked together, it took them 5 days. How long would it take each to paint the house? So, i know how to setup the problem, but i'm not sure what steps I need to take to solve. This is...
April 7, 2016

physics
The system of small objects shown in the figure below is rotating at an angular speed of 2.0 rev/s. The objects are connected by light, flexible spokes that can be lengthened or shortened. What is the new angular speed if the spokes are shortened to 0.15 m? 1.0m x 1.0m distance.
April 5, 2016

physics
A 1400-N uniform boom at ϕ = 70.0° to the horizontal is supported by a cable at an angle θ = 20.0° to the horizontal as shown in the figure below. The boom is pivoted at the bottom, and an object of weight w = 2250 N hangs from its top. (a) Find the tension ...
April 5, 2016

Math HELP!
For how many integers x does a triangle with side lengths 10,29 and x have all its angles acute. how do I know which side is the hypotenuse or does it not matter? Please give me an explanation.
April 4, 2016

Math HELP!
For how many integers x does a triangle with side lengths 10.29 and x have all its angles acute. how do I know which side is the hypotenuse or does it not matter? Please give me an explanation.
April 4, 2016

Science
Refracting telescopes use lenses. Reflecting telescopes use mirrors. However, both types of telescopes have something in common. How are both types of telescopes similar? A)They both magnify tiny nearby objects. B)They both reflect light that enters the telescope. C)They both ...
April 4, 2016

Science
Is it B?
April 4, 2016

Algebra
Diane Gray and Lucy Hoang together can prepare a crawfish boil for a lagre party in 4 hours. Lucy alone can complete the job in 2 hours less time than Diane alone. Find the time in which each person can prepare the crawfish boil alone. Round to the nearest tenth of an hour.
April 4, 2016

help my son's math
Hill crest public school held its annual skating party and 3/4 of the 480 students came.Of the students who came,1/5 brought skates from home. How many students rented skates?
March 31, 2016

US History
According to Black Elk, what atrocities took place at Wounded Knee? How did President Harrison describe these atrocities? Whom did Black Elk blame for the Wounded Knee Massacre? Whom did Harrison blame? According to President Harrison, what was the future of Native Americans? ...
March 30, 2016

US History
Discuss the different approaches of the federal government toward the Plains Indians
March 30, 2016

algebra
A 3 by 5 inch picture is put into frame with a mat that has width x. Draw picture inside the frame, write the expression of the width and length of the frame AND the picture together. If the total area of the frame with the picture is 35 in ^2, find the width and length of the...
March 30, 2016

math
The length of a rectangle is four more than five times its width. Its perimeter is 92 inches. Find its dimensions​ length and​ width.
March 9, 2016

algebra
The length of a rectangle is two more than four times its width. Its perimeter is 54 inches. Find its dimensions​ length and​ width.
March 9, 2016

algebra 1
What is -16x^2+96x+200?
March 6, 2016

algebra 1
What are two methods of solving 4x^2+16x+9?
March 6, 2016

physics
The front 1.20 m of a 1,350-kg car is designed as a "crumple zone" that collapses to absorb the shock of a collision. (a) If a car traveling 21.0 m/s stops uniformly in 1.20 m, how long does the collision last? s (b) What is the magnitude of the average force on the ...
March 3, 2016

Math
1) a) Decide if (q  ( p~ q))~ p is a tautology using propositional equivalence and the laws of logic. b) Prove that the following argument is valid: q q r p r p ~ _________ ~    c) Replace p, q and r in 1b) by statements and ...
March 3, 2016

Math
A bag contains 5 red and 4 green discs , three discs are randomly drawn from a bag what is the probability at least 1 is red and the probability at most one is green?
March 3, 2016

physics
A block of mass m = 5.90 kg is released from rest from point circled A and slides on the frictionless track shown in the figure below. (Assume ha = 7.30 m.) point b is 3.20 m and point c is 2.00m. (a) Determine the block's speed at points circled B and circled C. point ...
March 3, 2016

Geometry
i meant: 2a-5 Not b=2a-25! Is this from prentice hall geometry, Potter School anyone?
February 24, 2016

Geometry
i meant: 2a-5 Not b=2a-25!
February 24, 2016

Geometry
2a -25 subtract and add so b is alone on one side, then divide by five on the whole equation to get what b is. We will survive Geometry!
February 24, 2016

English
You are assigned to write an essay which must maintain the indicative mood throughout. Which of the choices below would need to be removed or revised? A) Have you ever wished for anything so badly that it hurt not to have it? B) I often walk down the street near my house, ...
February 24, 2016

English
okay I got it I think my final answer is B.
February 23, 2016

English
No not a its D.
February 23, 2016

English
A ?
February 23, 2016

English
Which sentence uses an infinitive as a noun? A) The best movie to watch is coming on TV tonight at 9:00. B) Phil wanted to play video games, but he finished his homework first. C) The cheerleaders traveled to the away games to cheer for the football team. D) Rachel is the ...
February 23, 2016

math
What is the relationship among the numbers and symbols in the expression (14 – 4) ÷ 2? Choose all answers that are correct. A. The difference between 14 and 4 is doubled. B. The difference between 14 and 4 is split into 2 parts. C. The expression has a value equal ...
February 22, 2016

science1002
how many moles are present in 25ml of 0.1m of na2co3
February 21, 2016

physics
A 4.00 kg block is pushed along the ceiling with a constant applied force of 85.0 N that acts at an angle of 55.0° with the horizontal, as in the figure below. The block accelerates to the right at 6.00 m/s2. Determine the coefficient of kinetic friction between block and ...
February 21, 2016

physics
7.–/3 points SerCP9 4.P.063.My Notes Question Part Points Submissions Used A box rests on the back of a truck. The coefficient of static friction between box and bed of the truck is 0.355. (a) When the truck accelerates forward, what force accelerates the box? the ...
February 21, 2016

physics
A hockey puck is hit on a frozen lake and starts moving with a speed of 14.0 m/s. Five seconds later, its speed is 5.50 m/s. (a) What is its average acceleration? m/s2 (b) What is the average value of the coefficient of kinetic friction between puck and ice? (c) How far does ...
February 21, 2016

trigonometry
I need help solving this problem. Question: At what points will the line y=-x intersect the unit circle x2+y2=1?
February 14, 2016

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