Total # Posts: 3,009
A certain elevator car has mass 2200 kg and is lifted by cables driven by an electric motor. The efficiency of the lift system (motor, pulleys, cable, etc.) is 67.0%. As the elevator car moves at constant speed of 3.0 m/s it encounters 220N of friction coming from its tracks. ...
December 1, 2013
A steel section of the Alaskan pipeline had a length of 65.1 m and a temperature of 15.8 °C when it was installed. What is its change in length when the temperature drops to a frigid -31.2 °C?
November 30, 2013
Could you help me answer these questions using William Cullen Bryant's poem, "The Prairies?" Thank you so much! I've attached a link to the poem. The poem text is widely available online if you just google the title/author Here are the questions I am ...
November 27, 2013
what would be an example of a parameter? i'm confused. i'm given this problem: How much time do undergraduate students at GMU spend each day reading and sending email? A survey was conducted by a graduate student asking students in the Johnson Center the above question...
November 24, 2013
A gyroscope consists of a uniform disc of mass radius M= 1 kg and radius R= 0.3 m . The disc spins with an angular speed ω= 200 rad⋅s-1 as shown in the figure below. The gyroscope precesses, with its axle at an angle 30∘ below the horizontal (see figure). The ...
November 20, 2013
A woman on a bridge 75.0m high sees a raft floating at a constant speed on the river below. She drops a stone from rest in an attempt to hit the raft. The stone is released when the raft has 7.00m more to travel before passing under the bridge. The stone hits the water 4.00m ...
November 19, 2013
A coin rests 18.0 cm from the center of a turntable. The coefficient of static friction between the coin and turntable surface is 0.390. The turntable starts from rest at t = 0 and rotates with a constant angular acceleration of 0.850 rad/s2. (b) At what angular speed (ω...
November 12, 2013
A ball is thrown horizontally from the top of a building 45.2 m high. The ball strikes the ground at a point 78.9 m from the base of the building. The acceleration of gravity is 9.8 m/s 2 . Find the time the ball is in motion, initial velocity, and x and y components
November 10, 2013
Tom the cat is chasing Jerry the mouse across a table surface 2.4 m oﬀ the ﬂoor. Jerry steps out of the way at the last second, and Tom slides oﬀ the edge of the table at a speed of 4.8 m/s. Where will Tom strike the ﬂoor? The acceleration of ...
November 10, 2013
I need an example thesis for a research paper. It can be about pretty much any music as long as its before 1750. (pretty much everything from Ancient Music - The Baroque period). Thanks in advance!
November 4, 2013
A hockey puck sliding on a frozen lake comes to rest after traveling 272 m. If its initial velocity is 3 m/s, what is its acceleration (assumed constant)? Answer in units of m/s2
October 29, 2013
Computer Programming using python
def test(): index = 1 prev_index = 0 count = 0 global largest largest = '' test = s[prev_index] while count < len(s): if ord(s[index]) > ord(s[prev_index]): test += s[index] index += 1 prev_index += 1 elif ord(s[index]) == ord(s[prev_index]): test += s[index] ...
October 24, 2013
When 1.00 kg lead (specific heat = 0.13 J g -1 C -) at 100.0 C is added to a quantity of water at 28.5C, the final temperature of the lead-water mixture is 35.2 C. What is the mass of water present?
October 21, 2013
How much heat, in kilojoules (kJ), is required to raise the temperature of 2.50kg Hg(l) from -20.0 to -6.0C? Assume a density of 13.6g/ml and a molar heat capacity of 28.0 J mol -1 C -1 for Hg(l). Please helpppppp .... thanks in advance
October 21, 2013
MATH MS.SUE HELP PLEASE!
Could somebody help me I don't understand any of this. Could someone show me or tell me how to work the problems? 1. Find the length of the hypotenuse of a right triangle with the legs of 9cm and 12cm A.8 B.21 C.15 D.225 2.The length of a hypotenuse of a right triangle is ...
October 18, 2013
Math - Trigonometry
Well think about it. The period of cos(x) is 2pi, 114pi = 358.14, so cos(x) repeats 114/2 = 57 times. So the answer is 57*2 = 144, but since cosine is split over y axis on the first period (calculatorsoup dot com/images/trig_plots/graph_cos_pi.gif) we add 1 to 144, and get 145.
October 15, 2013
A rocket moves upward, starting from rest with an acceleration of 28.1 m/s2 for 5.21 s. It runs out of fuel at the end of the 5.21 s, but does not stop. How high does it rise above the ground?
October 5, 2013
In one revolution a wheel moves forward a distance equal to its circumference. This is because the wheel Always in contact with the floor. 1)A trundle wheel clicks everytime. What is the radius of the wheel
October 5, 2013
A running track has 8 lanes each a meter wide.Each"straight" is 100 meters long. The distance around the track for someone running in the middle of the inside lane is 400 meters. What is the distance around the track for someone running in the middle of the outside ...
October 5, 2013
This is part of Coursera class final exam (From the Big Bang to Dark Energy by Hitoshi Murayama). I think it's OK to learn about the Higgs via lectures or web searches. But asking for folk to answer the question is cheating.
October 1, 2013
For Question 1: 2440 Total PV output = 1000W/m2×18%×10m2=1800W PV module costs = 1800W×0.8/Wp=1440. Non-modular costs = 100/m2×10m2=1000. Total cost = PV module costs + non-modular costs = 2440.
September 29, 2013
Help a brother out!!! please!!!Nitroglycerin, C3H5N3O9 decomposes to form N2,CO2,H2O, and O2 4(C3H5N3O9)-> 6N2+12O2+10H20+O2 a)How many grams of water would be produced if 75g of nitroglycerin decompose? b)The creation of 3.89 moles of C02 would require how many grams of ...
September 28, 2013
Explain whether slavery or representation was the main cause of disunion. You may incorporate two of the following to support your answer -The Missouri Compromise -The Free-Soil Movement -Compromise of 1850 -Kansas-Nebraska Act, 1854 -Bleeding Kansas Dred Scott v. Sandford
September 26, 2013
Networks are often set up in the client/server network arrangement. Raheem has learned that this is a very common type of network arrangement. Discuss two things that Raheem should be concerned with if he decided upon a client/server network arrangement?
September 18, 2013
Okay, I'm in a calculus class but stuck on some algebra...it's not crucial that I get the answer to this but I'm wracking my brain because I can't remember how the following is obtained; if you can show me how this is done in steps I'd greatly appreciate it...
September 8, 2013
Statistics / Business
According to the National Humane Society, "Stray Cost" or the cost of the care and feeding for a stray dog is $419.00 per year. This amount does not include veterinarian care, but only food, water and shelter. It was found that the standard deviation of this "...
September 8, 2013
Scientists generally agree that Earth is getting warmer due to what's called the greenhouse effect. A greenhouse used for plants stays warm because sunlight and heat coming through the glass roof are mostly trapped. The heat doesn't radiate back into the atmosphere ...
September 6, 2013
Imagine that there is a fire in your house or apartment, and you only have 5 minutes to grab your possessions and get out. Everything you leave behind will be destroyed. What would you grab? Why? When you think about what you left behind, are you sad that you lost it or happy ...
August 9, 2013
A die is rolled 600 times. The face with six spots appears 112 times. Is the die biased towards that face, or is this just chance variation? The null hypothesis is: he null hypothesis is The die is biased towards the face with six spots. The chance that the face with six spots...
July 31, 2013
How much space does the dining area take up? 100 guests, each guest requires 3m2 in the dining area, the average mass of each guest is 65 kg, and the average density of the dining area is 10kg/m2 How I can resolve this problem?
July 28, 2013
Physics (help steve)
A thin aluminum ring hangs vertically from a torsion spring. A torsion spring when twisted exerts a restoring torque given by τ=−κθ where θ is the angle of twist. Suppose that the ring undergoes small torsional oscillations while it is being cooled ...
July 5, 2013
In the following figure m_1 = 20.0kg kg and á alpha = 50.9 ∘ ^\circ. The coefficient of kinetic friction between the block and the incline is ì k = 0.40 What must be the mass m 2 of the hanging block if it is to descend 9.00m m in the first 3.00s s after ...
July 4, 2013
Math (please help steve)
The Chicago Art Museum's Renaissance display consists of four hallways bordered around a square courtyard. A single guard is assigned to patrol the four hallways. When the guard starts working, he begins in one of the corners and walks clockwise. When he arrives at a ...
July 1, 2013
Calculus (help steve)
f(x)=−8x^3+6ax^2−3bx+4 has a local minimum at x=1 and a local maximum at x=3. If a and b are the local minimum and maximum, respectively, what is the absolute value of a+b?
June 28, 2013
(1,0) is a point on the parabola y=2x(x−1). From point A, point P is moving along the curve towards the origin O(0,0). As P→O, sec^2∠APO→N, where N is a positive integer. What is the value of N?
June 27, 2013
A(1,0) is a point on the parabola y=2x(x−1). From point A, point P is moving along the curve towards the origin O(0,0). As P → O, sec^2∠APO → N, where N is a positive integer. What is the value of N?
June 27, 2013