Total # Posts: 1,122
A sphere of mass 78 kg is attached to one end of a rope as shown in the figure below. It is found that the rope does an amount of work W = 3550 J in pulling the sphere upward through a distance 4.6 m. Find the work done by the force of gravity on the sphere. My work W= -78 * 9...
October 26, 2015
What is the concentration of Fe(III) with a stock concentration of .00025 M in a solution of 1 ml FeCl3 and 9 ml of HCl? 2 ml of FeCl3 and 8 ml of HCl? 3 ml of FeCl3 and 7 ml of HCl? 4 ml of FeCl3 and 6 ml of HCl? 5 ml of FeCl3 and 5 ml of HCl? I got .000025 .00005 .000075 ....
October 25, 2015
Complete combustion of 8.30 g of a hydrocarbon produced 26.7 g of CO2 and 9.10 g of H2O. What is the empirical formula for the hydrocarbon? My Work: First I tried to find the Amount of C and H in the product... Which I got 1 Mole of Carbon and 2 moles of Hydrogen... Now I'...
October 21, 2015
I have a question from an old exam that I need help to understand, i'm not sure where to start An electron in an electronically excited hydrogen atom undergoes a transition from a 6d to a 2p orbital, resulting in the emission of a photon. The photon strikes a metal surface...
October 15, 2015
I have a metal sheet of indium, and when a uv light with a wavelength of 265 nm is shone on it the surface ejects electrons that have a kinetic energy of 8.31x10^-20 J per ejected electron. I'm asked to find the threshold frequency, I need to know how to find it.
October 15, 2015
the decimal place right after the decimal is the tenths, the next is the hundredth, then thousandths, then ten thousandths, ect, in that pattern, so what is the hundred thousandths place?
October 15, 2015
bob is pushing straight down on the box, which is in the direction that the force of gravity is, so the force downwards is equal to 12+mg. Since there is no acceleration in the up/down direction, Fn=Fapplied=Fg
October 14, 2015
A particular style of sunglasses costs the retailer $80 per pair. At what price should the retailer mark them so he can sell them at a 20% discount off the selling price and still make 30% profit on his cost?
September 30, 2015
I realize i need to do "complete the square" and here is what i got... (4/4)x^2-(12/4)x+(61/4)=0 x^2-3x+15.25=0 x^2-3x=-15.25 x^2-3x+2.25= -15.25+2.25 (x-1.5)^2=-13 x=1.5 +/- sqrt(-13) I know i am wrong... help?
September 26, 2015
Estimate the speed in mph with which water comes out of a garden hose using your past observations of water coming out of garden hoses and your knowledge of projectile motion. (Take the inclination angle to be 45°, the initial height to be 1.0 m, and the range of the ...
September 6, 2015
1. 9 eggs, 6 baking mix, 1-1/2 cups of oil, 3 cups of water. You are just tripling the ingredients. 2.10.50 4.3cups of red, 1-1/2 cps of black, 3/4cp of white and orange. 5.30inch platter
August 15, 2015
A constant torque of 30m⋅N is applied to the rim of a 6.0-kg uniform disk of radius 0.20m .What is the angular speed of the disk about an axis through its center after it rotates 2.0 revolutions from rest?
June 3, 2015
An airplane is heading north at an airspeed of 500 km/hr, but there is a wind blowing from the northwest at 50 km/hr. how many degrees off course will the plane end up flying, and what is the plane's speed relative to the ground? So here is my work... 50cos(45)+500= 535....
May 28, 2015
An airplane is heading north at an airspeed of 300km/ hr, but there is a wind blowing from the northwest at 50km/hr. How many degrees off course will the plane end up flying, and what is the plane's speed relative to the ground?
May 27, 2015
SO this problem is a cosine law problem? And if i did the problem right... It should be 7276.412812... I changed the degree (130 degrees) to radians If i should not change the degree to radians... it should be 1822.498064...
May 21, 2015
Two planes leave teh same airport at the same time. one flies 20 degrees east of north at 500 mph. the second flies 30 degrees east of south at 600 mph. how far apart are the planes after 2 hours?
May 21, 2015
Find all solutions on the interval [0.2pi) A) -3sin(t)=15cos(t)sin(t) I have no clue... b) 8cos^2(t)=3-2cos(t) All i did was move around the equation to make an quadratic for B. so -8cos^2(t)-2cos(t)+3 = 0
May 7, 2015
1) Find the exact value of the expression: tan−1(tan(−120651/47π))... How do you find Tan(-120651/47pi)? I don't know how to find exact values, if it's not a recognizable value. 2)Find a simplified expression for tan(sin−1(a/5))... Because tan = ...
May 3, 2015
A company runs food service concessions for sporting events throughout the country. Their marketing research department chose a particular football stadium to test market a new jumbo hot dog. It was found that the demand for the new hot dog is given approximately by p=8−...
April 6, 2015
Gravel is being dumped from a conveyor belt at a rate of 30 ft3/min, and its coarseness is such that it forms a pile in the shape of a cone whose base diameter and height are always equal. How fast is the height of the pile increasing when the pile is 14 ft high? (Round your ...
April 5, 2015
Please tell me if i got this right... Fill in the blanks... The __Sum__ of the length of the hypotenuse of a __Right__ triangle is equal to the __Sum__ of the squares of the __Length__ of the other two __Sides__.
April 2, 2015
An open-topped rectangular box is to be constructed from a 24 inch by 36 inch piece of cardboard by cutting out squares of equal sides from the corners and then folding up the sides. What size squares should be cut out of each of the corners in order to maximize the volume of ...
March 20, 2015
An object is launched at 9.8 meters per second from a 73.5-meter tall platform. The object's height s (in meters) after t seconds is given by the equation s(t)= -4.9t(-4.9t) - 9.8t = 73.5. When does the object strike the ground? I literally have no idea where to start
March 17, 2015
The inflation rate in the united states in 2014 was about 1.3%. If prices go up by 1.3% per year, how long will it take for them to double? assume that prices are increasing continuously.
March 11, 2015
A concrete path of width 1m and thickness 10cm is to be placed around you pool. Find the number of cubic meters of ready mixed concrete required to lay the path. Additional Info: pool area is 25.75 without concrete around it. Thank You.
March 8, 2015
Please help! I have 30 ml bottle of 5% hydrocholric acid. Ned to dillute to make 200 ml of .01 M hydrocholric acid. I dont know how much of the bottle solution to add to how much distilled water to get 200 ml at .01 M
March 4, 2015
5% hydrocholric acid in 30ml (1 fl oz) - how to dillute to make 200 ml of .01 M? I think i need to first fin concentration solute /amount of solution x 100 .05/30 x100 = .166 Then i get lost!
March 4, 2015
An airplane travels with a speed of 145 mph in calm air. the wind is blowing with a velocity of 23 mph from N72degreesE. If the plane is headed in a direction N63W, find the magnitude of the speed and the direction of the airplane with reference to the ground. In what ...
February 24, 2015
A proton has an initial speed of 7·105 m/s. It is brought to rest by an electric field. a.) What is the magnitude of the voltage difference needed to bring this charge to rest? answer: 365.313*7v, WHY
February 22, 2015
A projectile on level ground is launched with a certain speed vi and has a downrange distance of vx what is its new downrange distance if it is launched with a speed of 4vi instead?
February 19, 2015
A man is on his apartment balcony 25m above ground level. He has a fire hose aimed directly at another man who is a ground level, a horizontal distance of 35m from the apartment block. The man on the balcony opens the nozzle and water travels with a speed of 18m/s. how far ...
February 18, 2015
Do i need to replace x to a number? or the question just asking to explain how x can become that equation like your answer ? if x = 0 , 9^x = 1 if x is positive, 9^x > 1 if x is negative 9^x < 1 There is no value of x which makes 9^x = 0 nor can 9^x ever be < 0
February 8, 2015
a child mass m slides down a slide 5 m high. the child speed at the bottom of the slide is 3 meters per second. what is the percent of mechanical energy the child has at the top of the slide. converted to kinetic energy
February 7, 2015
An open box is to be made from a flat piece of material 9 inches long and 6 inches wide by cutting equal squares of length x from the corners and folding up the sides. Write the volume Vof the box as a function of x. Leave it as a product of factors, do not multiply out the ...
January 22, 2015
It's been a minute since I have done much with algebra, but if you are looking to simplify I believe this is correct. First part cancels out so (b+c+a) / (b+c+a) = 1 Then you can remove the squares by dividing like variables. (1 + (b^2 + c^2 - a^2)) / (2*b*c) = (1 + b + c...
January 20, 2015
I was able to come up with the answers through trial and error, and the answer for the charge +q makes sense, but I don't understand why the answer for the -q is correct. Please help. A positive point charge +q1, a second point charge q2 that may be positive or negative, ...
January 20, 2015
Two is C. You can multiply any number by the decimal equivalent of the percentage you are interested in (i.e. 40% if 50 is 0.4 * 50) First one has me confused. Are they typed in correctly? 15% of 30 is 4.5 A. 15/30 = x/100 15/30 = 0.5, .5/100 = 0.005 Wrong B. 15/100 = x/30 15...
January 20, 2015
On Sept. 1, 2012, Parsons Company purchased $84,000 10 year 7% government bonds at 100 plus accrued interest. The semi-annual interest payment dates are June 30 and Dec. 31. Journalize the entry to record the bond purchase.
January 8, 2015
Oxygen gas can be generated by heating KClO3 in the presence of a catalyst. KClO3 KCl + O2 (unbalanced) What volume of O2 gas will be generated at T = 35°C and P = 764.0 torr from 1.51 g of KClO3? I got .414 L and used 22.4 L for moles of O2 What's going on??
December 17, 2014
Consumption of alcoholic beverages by young women of drinking age has been increasing in the United Kingdom, the United States, and Europe (The Wall Street Journal, February 15, 2006). Data (annual consumption in liters) consistent with the findings reported in The Wall Street...
December 16, 2014
In an electricity experiment, a 0.900g plastic ball is suspended on a 50.0cm long string and given an electric charge. A charged rod brought near the ball exerts a horizontal electrical force F⃗ elec on it, causing the ball to swing out to a 23.0∘ angle and remain ...
December 15, 2014
Jane has a bike with a 22-inch rear wheel. The wheel sprocket is 3 inches in diameter and the pedal sprocket is 4 inches in diameter (the sprockets hold the chain.) How fast in miles per hour is she going if she pedals at a rate of 100 revolutions per minute?
November 17, 2014