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  1. C

    Related rates

    a women is walking at a rate of 6 ft/sec across a bridge 40 ft above the water, a man in a boat is immediately below the woman on the bridge , at right angles to the bridge and at the rate of 4 ft /sec. how fast is the man and woman seprating at the end of 10 seconds what i have figured out...
  2. C

    Differentiation rule ?

    f(t) = 400t+70/t+1 represents the temp. in an oven and f(t) is in F degrees first i used the quotient rule and got 330/(t+1)^2 = f'(t) A) the rate of change in temp of the ove with respect to the time of 2 minutes after turnig the oven on and at 10 minutes i pluged 2 and 10 in...
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    Chain rule

    g(x) = (4+csc^2(3x))^2 this is what i got 1/2(4+csc^2(3x))^-1/2 * d/dx (4+csc^2(3x) g'(x) = 1/2(4+csc(3x))^-1/2 (1+cot3) did i go about this correct to get the answer or did i mess it up at the diretive part? joe
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    Struggling on this one

    y = x*square root of 3 + 2sinx find the x coordinate on (0,2pie) of the points where y has a horizonal tangent line I am really lost and struggling on getting this started :cry: :confused: thanks joe
  5. C

    Calculus answer check

    Am I goong about these two problems correctly? A) F(x) = (xsinx)(cosx) find F'(x) f(x)*d/dx(g(x) + g(x) * d/dx F(x) product rule F'(x) = xsinx d/dx (cosx) + cos x d/dx xsinx = xsinx*(-sinx) + cos x *(xcosx) = -xsin^2 x^2 + xcos^2 x^2 is that right B) F(x) = xe^x/ x^2 +...
  6. C

    How to approach this problem

    If F(x) -64/x^2 and it wants me to find an equation that decribes its position at (8,-1) which way do you think is best to find this out using the division of deritives or get it by limts
  7. C

    Vertical asymptotes

    The question is fine a equation f(x) that has a vertical asymptotes of X=1and X=3 and a horizontal asymptotes of Y=1 A) (x-1)(x-3) / y-1 = x^2-4x+3 / x-1 OR B) (x-1) /(x-1)(x-3) = just the oppsite of above is any of these correct? I think B is correct but right now I can't...
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    One more limit ?

    Can anybody help me get started on this the radical in the Numerator gots me lost. F(x) = 3-sq root x / 9-x has a removable discontinuity at x=9. define a new function g(x) such that g=f everywhere except at x = 9 , but is continuous everywhere. :confused: thanks joe
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    5 years since my last math class

    It has been at least 5 years since my last math class and I am kinda struggling. The question is: Use the intermediate value theorem to show that there is a root of ln x = e^-x on the interval (1,2). Find the correct root to 3 decimal values What i have so far f(1) = ln 1...
  10. C

    Struggling in econ

    :confused: Suppose a firm in a perfectly competive industry is producing a output of 10 units. The firms total revenue at this output is $80 and its total cost is $30. The firms marginal cost associated with the 11 unit of a output is $12. What can i say about an increase in production should...
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    Index of refraction

    In this figure the path of the light passes from air to glass. Calculate the index of refraction n1 = air = 1 n2 = glass = ? Sin theta 1 = 30degrees sin theat 2 is = 20 degrees formula used n2 = n1*sin theta 1 / sin theta 2 sin of 30/ sin of 20 = n2 = 1.46 is this correct hope the...
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    Concave mirror

    if a double concave mirror with a focal length f = -20 inches is used , where does the image seem to be located , if the image is 30 feet away from the lens first i converted the 30ft to inches and got 360inches used formula 1/p + 1/q = 1/f .0028 + 1/q = -.05 1/q = -.053 q = -18.9...
  13. C

    Mirror question

    The rear view on the passenger side of late model cars warn us theat objects may be closer than they appear. I think the mirror used is convex. But why is that type of mirror selected? thanks joe
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    Light rays through a window pane

    I know a prisim can be used to disperse white light into colors. This does not happen when a beam of light passes through a window pane.Why not?( the light may or may not be entering the glass window along the normal. The light does not disperse into colors). thanks
  15. C

    Answer check / little help

    A proton traveling at 3E6 m/s enters a region where the electric field has a magnitude of 3E5 N/C. The electric field is uniform and slows the proton's motions. a)calculate the distamce the proton will travel before coming to a momentary halt? B)Calculate the decel. of the proton and the...
  16. C

    Going in right direction electric field

    The question is a charge object has a mass of 9.11E-31 kg and a charge of 1.602E-19 coul. Calculate the strength of the electric field that would provide a force equal to the weight of the charged object E = Fe/m 1.602E-19 / 9.11E-31 E = 1.76E 11 joe
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    Zener circuit help

    This is what i have so far the knowns Vs= 50v Vz = 10 v Iz = 32mA R1 = 1K ohm Rl =? "potentmeter" i just got the multisim program and could draw the cir if need be R1 is in series with the source and the zener and rl are in parallel it wants me to determine the range of Rl, Il...
  18. C

    Transistor ?

    The emitter current in a certian npn transitor is 8 mA. If .8% of the minority carrier injected into the base recombing with the holes, find the base current , collector current and the exact value of alpha i am not sure how to get this started thanks joe
  19. C

    Determine the change in internal energy of boiling water

    Determine the change in internal energy of 1 kg of water at 100 degrees C when it is fully boiled. Once boiled this volume of water changes to 1671 Liters of steam at 100 degrees C Assume the pressure remains constantat 1 atm things i know 1 L =1E-3 m3 1atm = 1.013E5 N/m2 1 L = 1000 cm3 =...
  20. C

    Internal energy

    Seem to have ran into a brick wall with this problem Determine the change in internal energy of 1 kg of water at 100 degrees C when it is fully boiled. Once boiled this volume of water changes to 1671 Liters of steam at 100 degrees C Assume the pressure remains constantat 1 atm things i know...
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    How much has the cable stretched?

    A truck is pulling a car out of a ditchwith a steel cable that is 9.1 meters long and has a radius of .5cm. When the car just begins to move the tension of the cable is 890N. How much has the cable stretched? converted .5cm to .005m area of the wire A = pie*r^2 Y = 20E10 (steel) used the...
  22. C

    Kenetic energy

    The question is Air is primarly a mixture of N2 and O2. Assume that each gas behaves as an ideal gas. If the temperture is is 293K calculate the kinetic energy of the air and calculate the Vrms of N2and O2 what I know is Kb = 1.38E-23 J/K mass of one molecule of N2 is 4.65E-26 mass of one...
  23. C

    Reverification of an answer Doc Al

    2)450ml of helium gas has a temp of -14 degress celicus and a pressure of 820 mmHg. What volumne would the gas occupy if the temp. increases to 14 degrees celicus and the pressure increases to 960 mm Hg my answer 426 ml 450(287K/259K)(820/960) is what i used i think i got it right now Doc...
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    Efficiency of a heat engine ?

    when i am calculating the eggiciency of a heat engine i have to convert the celicus to kelvis and used this formula eff = 1-(T cold/T hot)*100 fro example 302C = 593K 610C = 883K eff = 1-593/883 = about 32.8% efficient right ? thanks joe
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    Problem verification s

    I have 3 problems i would like to be reasured of the answer 1) 1200 liters of hydrogen gas has a temp of 50 degrees Celicus. To what temp would the gas have to be lowered so that the volumn would be 600 liters. my answer is -111.65 degrees celicus 2)450ml of helium gas has a temp of -14...
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    Fiber optic cabling

    Does any body know what the SC and ST connectors stand for [?] thanks joe
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    N-type semiconductor

    Does an n-type semiconductor exhibit a negitive charge, or is it electrically neutral? Why? I know that a n-type semiconductor is negitive charge thanks joe
  28. C

    Centripetal accel

    Truck weighs 6000 lbs The truck is going around a curve with a radius of 650 ft. The max friction force the road can excert is 1125 lbs.Its velocity needs to be calculated ft/sec. Now I now F=ma and Ff = m*(v^2/r) I also now that 1 pound = 4.448 N problem is i have 3 different answers by...
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    Not sure how to get started on on prob

    A truck weighs 6000 lb. The truck is going around a curvewith a radius of 650 feet. The maximum friction force the road can exert on the tires is 1125 lb. it wants me to calculate the velocity in ft/sec I am sorta lost on this an y help would be great thanks
  30. C

    Water fall question

    a waterfall is 30 m high and 10000 kg of water flow over it every second A) calculate the potential energy PE = mgh got 2.94E6 joules B) calculate the power delevered by the water of all the potential energy is converted to work F = mA F= 10000 * 9.80 f = 98000 w = Fm w 98000 *...
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