current

  1. I

    Solve For the Speed Of The Current

    A fish can swim 45 miles downriver in the same amount of time that it can swim 27 miles upriver. Solve for the speed of the current if the speed of the fish is 12 mph in still water. Show all of your work and explain your solution.
  2. B

    Increase in current as power is transmitted along a cable?

    I have a situation where I have some (real) power demand at the end of a transmission line (P_r) for a given receiving-end voltage (V_r). For a line 150km in length the mathematics for calculating the sending-end voltage and current is laid out below: Complex numbers... Impedance: Z = R +...
  3. M

    Current stored in capacitor

    Hello, If there is Capacitor rated for 100uF 50V we connect it directly to 12V and 21Amps supply The Energy store in it will be =1/2*C*V² E=1/2*100x10^-6*12*12 E=7.2x10^-3 Joules/sec So, P=V*I 7.2x10^-3 =12*I I=6x10^-4 Amps
  4. M

    How to calculate current through Resistance

    Hello, in this circuit i applied KCL and KVL i get these equation I1 +I3 - I2=0 eq1 KCL 28 - 4*I1 - 2*I2=0 eq 2 KVL 7 - I3 - 2*I2 =0 eq 3 KVL how to get individual value.
  5. K

    breakdown voltage and current

    when a voltage gap separted by, lets say an insulator like air, with sufficiently high voltage, aka, the 'breakdown voltage', the air will ionize, etc, and a 'spark' of current will flow with a larger gap, the required breakdown voltage will have to be larger... that is the break down...
  6. R

    Where to begin with this RMS question.

    If anyone could point me in the right direction with this question that would be great. I've uploaded the question and the equations for mean value and RMS. Mean value should = 200/pi and RMS value should = 70.7
  7. B

    Alternating Current of Gravity - possible path of asteroids orbiting eachother

    sorry duplicate of http://mymathforum.com/physics/49511-alternating-current-gravity-possible-path-asteroids-orbiting-eachother.html
  8. B

    Alternating Current of Gravity - possible path of asteroids orbiting eachother

    Every other mass goes up over and down while masses between them go opposite direction and down under and up and continue as a sine wave (or approximation of it?). By using gravity slingshotting (like a spaceship takes some of the moon's energy, lowering it toward earth, to accelerate around...
  9. Chikis

    Find the speed of the current

    A boat travels at 8km/hr in still water. A man sails 5 km/hr upstream, then back to his starting point. If the total time he takes is 1hr30mins, find the speed of the current. I may not be able to solve this problem because I don't know how the upstream and downstream movement of the boat...
  10. T

    Trig question involving current

    Can anyone help me as I am really struggling with this question. Thank you to anyone who can assist me. The instantaneous value of current i, at t seconds is shown by: i = 15 sin(100?.t + 0.6) find the value of: a) the amplitude b) the period c) the frequency d) the initial phase...
  11. M

    Solving the current through a glass furnace

    Hello Guys, I've got a project I need to do and it involves modelling a electric glass making furnace and calculating the resistance between electrodes (which are a way of heating the glass) and from there calculating the current and power going into it. I've found these two papers on the...
  12. G

    Finding Current Changes Without V Or R?

    This is some stuff I'm working on for class, and I'm having a hell of a time trying to understand it for some reason, even though it is very simple stuff. I don't want answers, I want to know and understand how to solve these problems and would appreciate any assistance from anyone who can help...
  13. K

    Probability of flow of electric current.

    Given failure intensities: \lambda_1=\lambda_2=0.05, \; \lambda_2=\lambda_3=\lambda_4=\lambda_5=0.08, \; \lambda_6=\lambda_7=0.0178 (nominal state). After burnout of any element intensity of electric current in other i-th element increases n_i times and failure intensity increases n_i^2 times...
  14. R

    Current through a wire.

    1 )) A circular loop of a wire is held in a uniform magnetic field, with the plane of the loop perpendicular to the field lines. Which of the following will not cause a current to be induced in the loop? a) Crushing the loop; b) rotating the loop about an axis perpendicular to the field lines...
  15. R

    How can a changing magnetic field induce an electric current

    Hi all, How can changing magnetic field to induce an electric current ? Can you give me Faraday’s law, in simple words ?
  16. P

    how to find current speed?

    Hi A car was moving for 8 minutes & was accelerating constantly. What is the speed of this car (Km/h)? by the time it reached 19/12 Km? Speed formula is V=s/t Answer is: 95Km/h Question, Why 95Km/h ? I understand that, a car must keep moving for 1 hour & then I know its speed in Km/h. But...
  17. B

    Find previous weights from current weights & percent change

    Hi Say that I have a stock portfolio with stocks that at the end of the day have the following weights: Stock A : 10% Stock B : 15% Stock C : 40% Stock D : 35% The change in stock price during the day was: Stock A : +5% Stock B : +20% Stock C : -10% Stock D : +50% From this information, can...
  18. J

    My Current Korean Math Textbook

    http://mid.imath.tv/answer/12.pdf This is the Korean math textbook (Calculus I). I would like to share how other country's math books look like.
  19. K

    A Current Age Puzzle

    The sum of the current age of Frank and Gavin is 44 years. At present, Frank is twice as old as Gavin was when Frank was half as old as Gavin will be when Gavin is three times as old as Frank was when Frank was three times as old as Gavin. Determine the current ages of Frank and Gavin from...
  20. K

    A Current Time Puzzle

    The current time is precisely 9*A minutes past B o'clock in accordance with a 12 hour analogue clock; where A is a positive integer. It is observed that the hour hand is precisely A minute marks ahead of the minute hand. Determine the current time from the information inclusive of the...