resistance

  1. P

    Mastering physics question!!!!

    I thought it was B, H but that is not correct
  2. K

    Resistance Maze

    I am trying to understand the difference between two paths of traveling current and why one is "right" and why the other is not. So the situation is this: All resistance are 4ohm and all batteries are ideal and have an emf of 10V. I am trying to solve for the current, and I have drawn two...
  3. M

    Resistance combinations help

    A little bit confusing the way this circuit was set up if you can help it would be great questions are equivalent resistance current through 18 and 12 ohms resistor power dissipation in 4.5 ohm
  4. K

    Calculate the total resistance of the currents in the conductors U = 120 V

    Calculate the total resistance of the currents in the conductors U = 120 V
  5. D

    Armature resistance

    Hello All, I have been given this question and although I have equations to work everything else out I cant find one for armature resistance. A d.c. self-excited shunt generator has a field resistance of 160Ω. The generated emf is 420V and it supplies a load of 55kW Calculate the armature...
  6. I

    Does this show atmospheric pressure or air resistance?

    Please help a discussion we're having here. The demo in question is attached. I had to do this demo as the very first introduction to pressure for K8 students. It's supposed to show that there is atmospheric pressure. I don't see it being much to do with pressure as much as air resistance...
  7. I

    Does this show atmospheric pressure or air resistance?

    I'm teaching at a private school and the very first demo shown to Yr 8 Science students to explain air pressure was this as shown in the attachment. I've seen similar experiments online all claiming to show that there's atmospheric pressure. However, I see it as showing air resistance...
  8. S

    Physics Software Calculate Nichrome Resistance

    Hii Friends!!! I am pursuing 9th grade in Chennai. As I am a week in physics problematic questions I was frustrated in studying that subject. But the golden opportunity to score good marks is getting full marks in physics problems. So, I started surfing in net for an easy method to solve...
  9. B

    Question for the resistance of the wire

    I think about that question many times for few days, but I still cant find out the correct answer! Maybe my steps are somethings wrong, please advise me! Thanks! A copper rod, 0.4m long and 4.0mm in diameter, has a resistance of 550μΩ at 20℃. Calculate the resistivity of copper at that...
  10. R

    equivalent resistance circuit problem

    Hi! I have a problem finding equivalent resistance for the following circuit. I can't see how to solve it... I would really appreciate help with it. Note that resistors are the same size - R0=3ohms.
  11. G

    resistance

    can someone help me with this please thanks
  12. G

    need some help with this one on resistance

    can someone please help with this one thanks in advance
  13. K

    Train's Frictional Resistance

    This is my first post so apologies in advance for any mistakes. I am doing some old exam questions and need some help on one to make sure I have done this right. (My dad thinks I have done this incorrectly) Thanks. The question: "A train is made up of a locomotive of mass 60 tonne and three...
  14. J

    Equivalent resistance of circuit

    How do you find the equivalent resistance between the points A and B? I don't see any paralel nor series resistances there, yet this must have a solution :P
  15. D

    Effect of Temperature on the resistance of a conductor.

    Hi, I am doing a research on the effect of temperature on the resistance of conductors. I have the data and have made the graphs of resistivity vs temperature but now I am unsure of how to analyze the graph. I have the slope of the graph, y-intercept as well as the R^2 Value. How can I use this...
  16. Q

    Ball thrown upwards with air resistance

    A ball is thrown vertically upward from ground level. Lets say the highest point the ball reaches is point A. Taking air resistance into account, am I right to say that it takes a longer time for the ball to go from point A to the ground than for it to go from the ground to point A because it's...
  17. S

    Total Resistance w/ switches

    point a(beside r1) is on top and point b(beside r3) is below Need to get the Total Resistance from a to b When: a. all switches are open b. only switch 3 is closed c. only switch 3 is open d. only switch 2 is closed my answer: a. so only r1 + r2 + r4? = 35 ohms b. not sure because...
  18. P

    Resistance...

    When we heat any metal, its resistivity increases due to expansion of particles. But when we give heat to metal or any substance, the particles move away(like solid to liquid state particles). How it is work in Resistance?
  19. B

    quadratic air resistance

    Hello A cricket ball is fired vertically upwards with quadratic air resistance. So only two forces act on the ball. W= -mgi R= -CD^2Vi So using Newton's second law: v= velocity at time t and D is the diameter of the ball. ma = - mg - CD^2v and a= -g - ((CD^2v)/m)...
  20. R

    Graphite's Coefficient of Temperature Resistance

    Why does graphite has a negative coefficient of temperature? It is a pretty good conductor which is quite similar to the metals. But metals have positive coefficient of temperature whereas graphite is negative. Would someone please explain why is that? Help will be greatly appreciated(Nod)(Nod)