Search results

  1. J

    Problem Calculating a limit with a square root, i'm stuck

    I discovered that that is the conjugate and I came out with this: 27-6sqrt(t)-tsqrt(t) ---------------- 9-t So in other words, that limit does not exist. Is that right?
  2. J

    Problem Calculating a limit with a square root, i'm stuck

    Problem Calculating a limit with a square root, I'm stuck :( Homework Statement The limit is equation 9-t / 3-sqrt(t) as t approaches 9 I'm stuck on the how to simplify this? Thanks for any help. Homework Equations The Attempt at a Solution
  3. J

    How to get Formula from a Cubic Graph

    I'm sorry but both of those answers made no sense...
  4. J

    How to get Formula from a Cubic Graph

    Homework Statement The figure shows the graph of a cubic polynomial. The function graphed is f(x)= Hint: You may write the function as f(x) = a(x-b)(x-c)(x-d) where b, c, and d, are integers and a is a fraction. Homework Equations The Attempt at a Solution I'm lost...
  5. J

    How to Factor

    Homework Statement How would you solve this problem: x^2 - 5x >= 0 Homework Equations The Attempt at a Solution I think it might be something to do with the Quadratic Formula?
  6. J

    Basic Boolean Minimization

    Actually would I be correct in saying that all like terms would be combined? because D'+D'+D'=D' so the simplified form of the equation above would be AB'+D' Is that right or am I completely crazy?
  7. J

    Basic Boolean Minimization

    Homework Statement I came to an equation which looks like this: AB'D' + AC'D' + CD' I know I can simplify out the C to this AB'D' + AD' + D' Any further simplification available (And am I simplifying properly so far?) Thanks Homework Equations The Attempt at a Solution
  8. J

    Fraction Simplification of Impedances and Resistances

    Let me throw another one out there to hopefully make it easier to understand (don't worry about the transfer function) so 2.2e3/2.2e3+i2pi10e-3 How would that be simplified or in simpler terms a/a+b How would you simplify that The problem above would be i*2pi*f*L/R+i*2pi*f*L f is the...
  9. J

    Fraction Simplification of Impedances and Resistances

    My algebra is really rusty, anyway I'm trying to simplify a Transfer Function so I have H(jw)=ZL/R+ZL so ZL is the impedance of an inductor and R is the impedance of the Resistor, my question is how would I go about simplifying that transfer function into it's simplest form? Thanks...
  10. J

    Engineering Circuit Simplification, did I do this right?

    Oh yeah your right, thanks for catching that.
  11. J

    Engineering Circuit Simplification, did I do this right?

    Oh and Quick question about Calculating Vb I know that I can use the Voltage Divider Rule to get it (I did that for Va) For Vb would I use the total impedance of all the impedances above the 820 ohms as say Z1 and then the impedance of the 820 Ohm resistor so it would be Vb=V*...
  12. J

    Engineering Circuit Simplification, did I do this right?

    I'm glad it's right, The book tries to simplify things by adding the ohms to help us realize that impedance is similar to ohms when the book get's more complicated it shows the actual capacitance. So I guess the book is kind of in "Training Wheels" mode at the moment :)
  13. J

    Engineering Circuit Simplification, did I do this right?

    I have a circuit here: And I simplified it like so: Did I do it correctly? Thanks, Jordan Homework Statement Homework Equations The Attempt at a Solution
  14. J

    Calculating Voltage Drop in an AC circuit

    i is what you would actually put into a calculator i=sqrt(-1) or something like that.
  15. J

    Calculating Voltage Drop in an AC circuit

    i is what you would actually put into a calculator i=sqrt(-1) or something like that.
  16. J

    Calculating Voltage Drop in an AC circuit

    what is wrong with 32+i isn't that what the +j32Ohms represents? I thought j was used in electronics because i is used for current.
  17. J

    Calculating Voltage Drop in an AC circuit

    3. I'm just asking if impedance is equivalent to Resistance when it asks for the Impedance of a Resistor. 4. The equation given is Vs(t)=10sin(400t) and the Inductor L is 80mH so from those two values I came up with the following as the value of the Impedance of the Inductor...
  18. J

    Calculating Voltage Drop in an AC circuit

    Homework Statement I have a couple of questions about one of my homework assignments any help would be greatly appreciated. 1. How do you find the Voltage drop of a Resistor in an AC Circuit is it similar to DC? V=IR The Resitor value is 68 ohms and there is an 80mH inductor in front of...
  19. J

    Algebra Help

    Sorry to bash on Physics websites but so far every Physics site I've found has had terrible design, poor teaching and organization. (similar to my teaching) With the exception of this site. (Best Physics Site I've found). I've found great resources for learning on every other subject through...
  20. J

    Algebra Help

    Cool thank you, And does anyone know a good site to learn Physics it's all going over my head in class.
  21. J

    Algebra Help

    Thanks for the help i'll try it, anyone know of resources that help you learn Algebra like this, it's really confusing to me. Thanks
  22. J

    Algebra Help

    Homework Statement mgh=1/2mv^2+1/2mr^2(v/r)^2 I need to solve for v, I'm really stuck on Algebra can anyone show me the steps I'd take to solve for V? Thanks Homework Equations The Attempt at a Solution Tried thinking it through but I'm getting stuck :( :(
  23. J

    Elastic Momentum

    I'm trying to take that into account but I'm still lost I think it's because I'm really rusty on Algebra
  24. J

    Elastic Momentum

    Oh yeah, good point
  25. J

    Elastic Momentum

    Ok, I used this equation: Vi1+Vi2=Vf1+Vf2 Vi1-Vi2=Vf1-Vf2 which would mean 15m/s + -15m/s=Vf1+Vf2 0=Vf1+Vf2 or Vf1=-Vf2 and 15m/s- -15m/s=Vf1-Vf2 15+15 30m/s=Vf1-Vf2 30m/s=Vf1-Vf1 what am I doing wrong?
  26. J

    Elastic Momentum

    I'm reading this: http://en.wikipedia.org/wiki/Elastic_collision#One-dimensional_Newtonian I'm confused on what the 'u' means under one dimensional Newtonian, does it just mean velocity? Thanks
  27. J

    Elastic Momentum

    The Kinetic Energy is conserved So I guess KEi=KEf or KEi=1/2M1Vi1^2+1/2M2Vi2^2 KEf=1/2M1Vf1^2+1/2M2Vf2^2 Where would I go from there?
  28. J

    Elastic Momentum

    Homework Statement Two elastic balls, one with mass m = 50 g and the other with mass M = 3m experience a head-on elastic collision after initially traveling in opposite directions at the same speed v = 15 m/s. Use the conservation of momentum strategy to obtain symbolic expressions and...
  29. J

    Parachutist jumping from plane Conservation of Energy

    Why though? is the plane traveling downward?
  30. J

    Parachutist jumping from plane Conservation of Energy

    Homework Statement A parachutist with mass m = 70 kg jumps from an airplane traveling at a speed v = 100 km/h at a height H = 2500 m and lands with a speed vf = 5.00 m/s. Use the “conservation of energy strategy” to calculate the change in internal energy of the system from just after the...
  31. J

    Potential Energy and Total Energy Negative

    no never, thanks for the help!
  32. J

    Potential Energy and Total Energy Negative

    well velocity could be I guess but it's square so it will always be positive.
  33. J

    Potential Energy and Total Energy Negative

    Ok, that makes sense, what does it mean when it says Total Energy? I think it means E=KE+PE E=1/2mv^2+mgh So Total Energy can be negative because Potential Energy can be negative, is that right?
  34. J

    Potential Energy and Total Energy Negative

    Homework Statement Explain why it is possible for potential energy and total energy to be either positive or negative, but kinetic energy is always positive Homework Equations The Attempt at a Solution I'm thinking that Potential Energy and Total Energy can be opposite and take...
  35. J

    Dot Product Calculation

    Homework Statement I have a problem for Work which looks like this: W=[(5.0i+2.0j)]N * [(2.0i+3.0j)]m =5.0i+2.0i+5.0i*3.0j+2.0j*2.0i+2.0j*3.0j Nm =[10+0+0+6]Nm = 16 How does that work? I don't understand? Homework Equations The Attempt at a Solution
  36. J

    Train Moving pulling two boxcars

    Homework Statement A train consists of a 4000 kg locomotive pulling two loaded boxcars, the first with a mass of 12,000 kg and the second with a mass of 16,000 kg. Assume that the boxcar wheels roll without friction and ignore aerodynamics. The acceleration of the train is 0.4 m/s2. With...
  37. J

    Elevator Questions

    Homework Statement You are standing on the floor of an elevator that starts, at rest, at the first floor of a building and then moves at constant speed to the tenth floor where it stops. Then you reverse the motion, ending where you started at the first floor. Describe the two important forces...
  38. J

    How long would it take to get to certain speed if you know Force forward and Mass?

    Homework Statement A frieght train has a mass of 1.5x10^7 kg. The wheels of the locomotive push back on the tracks with a constant net force of 7.5X10^5N, so the tracks push forward on the locomotive with a force of equal magnitude. (ignore aerodynamics and friction) how long would it take...
  39. J

    Derivatives and Vectors

    Homework Statement What does \mathbf{\frac{d\vec{x}}{dt}} mean? If my latex doesn't work that should be dx/dt where x is a vector? Thanks, I think it has something to do with derivatives if so how do I use it? Homework Equations The Attempt at a Solution
  40. J

    Calculate Acceleration of object in Circular motion

    Homework Statement A conical pendulum is made of a ball on the end of a string, moving in circular motion as represented in the figure below. The length L of the string is 1.70 m, the angle θ is 37.0o, and the ball completes one revolution every 2.30 s Calculate the acceleration of the...
  41. J

    Projectile launched over cliff

    Sorry I'm still a bit confused I first tried solving for Velocity Final LaTeX Code: v_f = v_i + at and did vf=0+2(-10m/s)(-75m) which gave 1500 and then I tried to solve for time using LaTeX Code: s = \\frac{(v_f + v_i)}{2}t and that came out with .1 second but I don't think I'm doing it right. :(
  42. J

    Calculating Speed of a motion of a Circular Object

    Alright, here is what I got R=L*sin(37) R=1 Diameter=2 Circumference=pi(2) Circumference=6.3 Speed=Distance Traveled/Time Speed=6.3m/2.3s = 2.7m/s Is that right?
  43. J

    Projectile launched over cliff

    Ok, the angle still throws me a little bit off, because won't the displacement (s) be more than 75 meters? Because it is shot up 40 degrees into the air? How do you take that into consideration? Thanks
  44. J

    Writing Equations for Position, Velocity, and Accelerations as functions of time

    I didn't really understand our teacher when he taught those formulas, is there a place I can look which teaches the formulas i'll need to use?
  45. J

    Projectile launched over cliff

    Homework Statement A projectile is launched with a speed of 50.0 m/s and an angle of 40.0o above the horizontal, from the top of a 75.0 m high cliff onto a flat valley floor at the base of the cliff. Assume that g = 10.0 m/s2 and ignore aerodynamic effects. How long does it take for the...
  46. J

    Particle Falling g=1m/s^2 how much time does it take to fall?

    Cool thank you very much for your help :D
  47. J

    Calculating Speed of a motion of a Circular Object

    Homework Statement A conical pendulum is made of a ball on the end of a string, moving in circular motion as represented in the figure below. The length L of the string is 1.70 m, the angle θ is 37.0o, and the ball completes one revolution every 2.30 s. Calculate the speed of the ball, by...
  48. J

    Writing Equations for Position, Velocity, and Accelerations as functions of time

    Homework Statement A projectile is launched with a speed of 50.0 m/s and an angle of 40.0o above the horizontal, from the top of a 75.0 m high cliff onto a flat valley floor at the base of the cliff. Assume that g = 10.0 m/s2 and ignore aerodynamic effects. Write equations for position...
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