Posts by frank
Total # Posts: 507
Calculus angle of elevation
Bob is wrong dx/dt = 3ft/s, dƟ/dt = ? 5ft/x = tan Ɵ Differentiating each side with respect to the time: (-5ft)/x^2 dx/dt=〖sec〗^2 ϑ dϑ/dt So dϑ/dt=(-5ft)/x^2 dx/dt.〖cos〗^2 θ We want to evaluate the change at the ...
December 9, 2014
A ball is thrown horizontally from the top of a building 45.9 m high. The ball strikes the ground at a point 121 m from the base of the building. The acceleration of gravity is 9.8 m/s2 . Find the time the ball is in motion. Answer in units of s Find the initial velocity of ...
November 16, 2014
A descent vehicle landing on the moon has a vertical velocity toward the surface of the moon of 22.7 m/s. At the same time, it has a horizontal velocity of 58.9 m/s. At what speed does the vehicle move along its descent path? Answer in units of m/s At what angle with the ...
November 16, 2014
The polynomial function defined by f(x) = 1 − x + x^2 − x^3 + ... + x^16 − x^17 may be written in the form f(y) = a_0 + a_1 y + a_2 y^2 + ... + a_16 y^16 + a_17 y^17, where y = x + 1 and a_i s are constants. Find a_2.
November 15, 2014
Find the points at which y = f(x) = x^11-6x has a global maximum and minimum on the interval 0 ¡ x ¡ 4 Round your answers to two decimal places. Global Maximum: (x,y) = (,) Global Minimum: (x,y) = (,)
October 29, 2014
Find the x- and y-coordinates of the center of gravity of a 4.00 ft by 8.00 ft uniform sheet of plywood with the upper right quadrant removed as shown in the figure below. The dimensions of the cutout are a = 4.50 ft and b = 1.70 ft. HINTS: Think of the board as being made of ...
October 28, 2014
Traveling at a speed of 19.5 m/s, the driver of an automobile suddenly locks the wheels by slamming on the brakes. The coefficient of kinetic friction between the tires and the road is 0.740. What is the speed of the automobile after 1.21 s have elapsed? Ignore the effects of...
October 18, 2014
A 20 kg object is acted on by a conservative force given by F = -3.0 x - 5.0 x 2, with F in newtons and x in meters. Take the potential energy associated with the force to be zero when the object is at x = 0. (a) What is the potential energy of the system associated with the ...
October 9, 2014
Suppose 1.2x10^3 kg of C is mixed with 2.4x10^5g oxygen gas and carbon dioxide forms. 1. write the reaction and balance 2.which reactant is the limiting reagent and which reactant is in excess 3. How many grams of carbon dioxide will be formed.
September 27, 2014
A 2.556g sample of baking soda (NaHCO3)decomposes to produce 0.876g of solid sodium carbonate. Caculate the theoretical yield and the percent yield of the sodium carbonate. The equation is: 2NaHCO3(s) -> Na2CO3(s) + H2O + CO2(g)
September 22, 2014
balanced equation =2 H(2)+ 1 O(2) -> 2H(2)O A. What mass of H2O would be produced from7.4 mg of O2 B. What is the volume of H2O would be produced from 7.4kg of O2. Density of water = 1.000g/ml
September 20, 2014
Country A is producing 4 units of X and 8 units of Y and country B is producing 4 units of X and 6 units of Y. The opportunity cost of producing more of A) good X is the same for both countries. B) good Y is the same for both countries. C) good X is lower in country A. D) good...
September 15, 2014
At some instant, a particle traveling in a horizontal circular path of radius 7.80 m has a total acceleration with a magnitude of 15.0 m/s2 and a constant tangential acceleration of 12.0 m/s2. Determine the speed of the particle at this instant(initial speed) and (1/8) ...
September 12, 2014
How would I make 500 ml's of a .35M NaCI solution. MW= 58.44 ( I know how to do the first part) How many micromoles of NaCI would be present in that solution? What would be the percentage of NaCI in that solution?
August 27, 2014
Suppose a study is done in which several random samples of people from a population are taken and polled on the number of hours per night they sleep. It is determined that the sample proportion for those who sleep at least 8 hours a night is 36%, and the 95% confidence ...
July 19, 2014
Thank you very much. I still have these sentences I'm doubtful about. My doubt is whether I should use the present perfect or the simple past (considering that it is the end of the school year) 1) Exercises for literary text analyses aimed at developing lexicon have been ...
May 12, 2014
Can someone check the grammar in the following sentences? Thank you in advance. 1) The nuclear power station can give our town a lot of energy and jobs to people. 2) We won't be able to use the farmland near the power station because it will be polluted with chemicals. We ...
May 12, 2014
The variables arr1 and arr2 have been declared as pointers to integers . An array of 10 elements has been allocated, its pointer assigned to arr1, and the elements initialized to some values . Allocate an array of 20 elements , assign its pointer to arr2, copy the 10 elements ...
March 16, 2014
Can someone help me with these sentences? Which of them are grammatically correct? Thank you very much in advance. 1) They are not able to dance well. 2) They can't dance well 3) Are you able to play the piano? 4) Can you play the piano? 5) Were you able to find the book ...
February 27, 2014
Can someone explain to me the difference between angry about and angry for (when a verb follows)? I think "about" is used in sentences like: he is angry about being in jail (Would "for" be possible in this sentence?) he is angry with me for being rude to ...
February 24, 2014
Can someone check if the questions and the sentences are grammatical? Thank you. 1)Can you fly with a Bergonian passport? 2) Why might visitors not be welcome on Seeland? 3) What are the citizens of the Aerican Empire like? 4) What happened to Danny when he accepted his friend...
February 20, 2014
Yes, I wrote the sentences incorrectly: Thank you He was seen to watch the TV He is still dependent on ... but independent of.... I was so angry WITH him FOR behaving like that in front of everyone. (about behaving would be a mistake?) The teacher was annoyed WITH me FOR ...
February 15, 2014
Can someone check if the following prepositions/verbs are correct? Thanks 1) I couldnt help CRYING 2) Its no use EXPLAINING it to him; he wont understand. 3) He was seen TO the watch. 4) I cant afford TO BUY it. 5) Norma is anxious ABOUT making the ...
February 14, 2014
Can someone check these sentences, please? I thank you in advance. 1) Lady Macbeth "becomes sleepwalking" 2) Cowardice is the ability to bear the sorrows of our life and to stay alive, while courage is facing death by committing suicide 3) We can't be sure about ...
February 14, 2014
Can someone please help me check the grammar in the following sentences? 1) I would like to inform people about the danger (after effects?) of having a nuclear power station near our town 2) I hope you will listen to our advice. 3) Animal and plant species will be in danger.
January 27, 2014
Can someone of you check these sentences, please? Thank you in advance. 1Complete the sentences with the correct form of should, must or have to. 1You _________ be worried. This test is very easy. (dont have) 2All the students _________arrive on time. (must) 3In my ...
January 24, 2014
Can someone check if the following questions are grammatically correct? Thank you. 1)Please Henry the VIII rule by focusing on the following: -Why he broke ties with the church -What the Act of Supremacy established -What political and social changes the reformation brought ...
January 20, 2014
Can someone tell me what's the British for the words "common trash barrels", "sorted trash", "regular kitchen" trash or food/garden waste? Thank you I'm quite environmentally friendly. I have three containers at home into which to sort my ...
January 14, 2014
Can someone help me with these sentences, please? Thank you very much in advance. I use the Internet to conduct school research, use translation programmes, use an online homework agency, do online shopping, play games, chat with my friends, send private instant messages, log ...
January 9, 2014
Can someone check these sentences, please? I need to prepare them for Tomorrow. 1) Air pollution is mainly caused by gases from factories and car exhaust fumes. It can cause acid rain, breathing problems and it can increase the risk of cancer. 2)The destruction of the ozone ...
January 8, 2014
Just one more thing. Which of the following sentences are grammatical? Thank you very much for your cooperation. 1.I spent most of my holiday at home. 2. I spent the greatest part of my holiday at home. 3. I mainly/mostly stayed at home during my holiday. 4.For the most part, ...
January 7, 2014
I left out these last sentences. Thank you. 1) My parents like my clothes style very much and not They like so much my clothes style. 2) My favourite style is the urban look because it is comfortable enough for school. 3) Each of you will have to join one of the four groups ...
December 20, 2013
Can you please check these sentences I'm doubtful about? Thank you very much. 1) My parents like my clothing style because they think that wearing practical clothes is the most important thing/most important is to wear practical clothes/ 2) I was given these trousers for ...
December 20, 2013
Can you please check these sentences? Thank you very much in advance and Merry Christmas! 1) The Key-Note begins with an extended description of Coketown, the fictional setting for the novel, which is based on Preston, now part of greater Manchester, where Dickens went in 1953...
December 18, 2013
I still have a few doubts. Thank you very much. 1) When I go to a party, I generally wear clothes which are smarter than the ones I wear for school. 2) I want to be original and on fashion (is it possible?) 3) What do you think of/about this coat? Are both "about " ...
December 13, 2013
I urgently need your help with a few sentences. Can you tell me which alternatives are possible? 1) What do you think of/about these shoes? 2) AlL the ones I have been shown are uncool 3) all of the ones I have been shown... 4) He was given two weeks by the judge in which to ...
December 12, 2013
A football arena measures 100ft. wide by 200ft long.The games are played on a similar rectangular field that's 150ft. long. What is the width of the football field? What is the perimeter of the football field?
November 10, 2013
A faulty odometer (mile indicator) on a car registers 6 miles for every 5 miles travelled. A t the start of a journey it reads 500 miles and at the end of the journey it read 560 miles. What distance has actually been covered?
November 2, 2013
Physics Classical Mechanics
Double star system answer - 9.859*10^17 seconds; keep on getting bungee jump wrong; I might be using the wrong equation. setting the equations to: 1/2*k*x^2=m*g*h; k = 2*m*g*h/x^2
October 21, 2013
Geosynchronous Orbit Equation: R^3=(T^2)*(G)*(M_p)/(4)*(pi^2) Time is in seconds T=1.6 earth days=38.4hrs=13824seconds or 1.38*10^4 seconds this the equation i I used to get my answer. b)V-escape=sqrt(2)*(m_planet)*G/R to do b you need a to solve; do not forget to take cubed ...
October 19, 2013
8.01 homework. I have difficulty with question no. 2. all my equations do not work-Rough Surfaces. Also, the period of oscillation got part a the rest is confusing and my answers do not check out. I thought this was a very difficult assignment to say the least. So far, I am ...
October 16, 2013
Father has red/green color blindness and is a hemophiliac. Mother is normal. Have two female children (Both are probably carriers). One female offspring marries a normal male. The question is what is the probability that their son is both color blind and hemophiliac? ...
October 14, 2013
A fan blade is rotating with a constant angular acceleration of +8.4 rad/s2. At what point on the blade, as measured from the axis of rotation, does the magnitude of the tangential acceleration equal that of the acceleration due to gravity?
July 16, 2013
A man is standing on a platform that is connected to a pulley arrangement, as the drawing shows. By pulling upward on the rope with a force the man can raise the platform and himself. The total mass of the man plus the platform is 94.7 kg. What pulling force should the man ...
June 30, 2013
To get an A grade on the test, you need a total score of more than 16 points. One of the students knows the correct answer to 6 of the 20 questions. The rest she guesses at random by tossing a coin (one toss per question, as in 4B). What is the chance that she gets an A grade ...
April 20, 2013
Four students measure the mass of an object, each using a different scale. They record their results as follows: Student A B C D Mass (g)49.06 49 50 49.1 E 49.061 Which student used the most precise scale?
March 2, 2013
The range of a set of data is 15, and the interquartile range of the same set is 12. Which of the following statements is true about the set? A) The two ranges are close together, so there is probably an outlier in this set B) The two ranges are close together, so there are ...
February 25, 2013
I'm stuck on this question, not sure where to start. can you show detail and explain so that it helps me to understand it. help please, thanks. The value of delta G for the conversion of 3-phosphoglycerate to 2-phosphoglycerate (2PG) is +4.4kj/mol. If the concentration of ...
February 9, 2013