Recent content by User1247

  1. U

    Courses Can I take the entire ENG 4U course for summer school and graduate this year?

    ENG4U credit You can get an ENG4U credit within a month if you can put in the time to get all the work done. www.ilc.org (in Toronto) offers it by distance and online, start whenever, very reasonable prices but you don't have much good access to help. www.virtualhigh school.com (Southwestern...
  2. U

    Problems with Electric Field questions

    Right, you can see: (-1E-9)r²-(4E-10)r+(4E-10)=0 before I found my mistake and (-1E-9)r²-(4E-10)r+(4E-11)=0 after I found my mistake. Those are quadratic equations.
  3. U

    A charge falls from infinity to within r of another charge, find velocity.

    Homework Statement Velocity of an electron that falls to r from infinity? An electron falls from infinity to r=10^-8m from a charge q1=4.8x10^-19C. What is the velocity of the electron? Homework Equations U=q1V V=kq2/r The Attempt at a Solution Potential energy change U...
  4. U

    Problems with Electric Field questions

    Homework Statement Find the point on the x-axis where the net electric field is zero for two particles of charges q1=1x10^-9C and q2=2x10^-9C. Assume q1 and q2 are 20cm apart. Assume q1 is located at x=0. I solved this but it's not the same as the book's answer.. GAH! What do you guys get...
  5. U

    Bubble Optics - Which colour would I see near the bottom?

    Homework Statement Hi everyone, I'm having trouble finding anything in the way of information on this problem. If anyone can help I'd appreciate it. I got a couple answers on yahoo answers but nobody could give an explanation for their answer. I want to understand where the answer comes...
  6. U

    Calculations in developing an Electrostatic Series

    Homework Statement Lab: rub each of a set of hard materials against a set of soft materials. Hold the hard materials near a suspended, negatively charged comb (wool rubbed) to determine the charge polarity and strength on the hard item. Create a list of the hard and soft items used in order...
  7. U

    Work example wrong in my text? (it's driving me bonkers)

    Thanks husky88, hopefully, when I send the work in, they will agree with my interpretation of "horizontal distance from top to bottom". I think it's a defensible interpretation since if we interpret 40m as the distance of the path traveled along the incline by the skater, then it's not...
  8. U

    How Is Work Calculated When Pulling a Wagon?

    Oops. 45 kg has been deeply lodged in my head from my adventures with the last post with the rollerskater going down the hill. Thanks for that mbrmbrg!
  9. U

    How Is Work Calculated When Pulling a Wagon?

    Ah! that is totally right, so if I allow the parent to be pulling at an angle to the horizontal, Fp would have a vertical component that would cancel out some of Fn and reduce Ff. I'll just pretend that the wagon is a point on the surface of the ground. Thanks, that ought to do it.
  10. U

    Work example wrong in my text? (it's driving me bonkers)

    AngeloG: Okay, if we choose to define x to be parallel to the hill's surface I now see that there is no acceleration or movement in the y direction from that perspective. I am new to work but here is what I see wrong with your solution: You use: ΣFy=0 (which I agree with given your...
  11. U

    How Is Work Calculated When Pulling a Wagon?

    Homework Statement Verbatim from the text: "In many neighborhoods, you might see parents pulling youngsters in a four-wheeled wagon. The child and the wagon have a combined mass of 50 kg and the adult does 2.2x10^3 J of work pulling the two 60 m at a constant speed. The coefficient of...
  12. U

    Work example wrong in my text? (it's driving me bonkers)

    AngeloG: Thanks for trying to help but I think you are reading the wrong question or something. The object is not fixed to anything, it is moving to the side and down. It is also accelerating to the side and down. Since there is no friction and there is a net force, it is indeed accelerating...
  13. U

    Work example wrong in my text? (it's driving me bonkers)

    nrged: Glad to hear someone say that the book is totally lost. I keep looking at the problem and it seems more obvious that the book is totally off. As for interpretation of the wording of the problem regarding what the 40m is: The book says: "the -horizontal- distance from top to bottom is...
  14. U

    Work example wrong in my text? (it's driving me bonkers)

    Hmm, lol, I am now possibly more confused than I was at the beginning. R1[Denverdoc]: "It could have been found more directly ... but still looks fine to me." My response: "it" is my solution? R3[Denverdoc]: "Edit: the approach of the book is ok, for frictional work its the only way to solve...
  15. U

    Work example wrong in my text? (it's driving me bonkers)

    Ok, book was wrong? Ok, so I take it that the book was just out to lunch and I should not injure my brain by devising various twisted understandings of work and interpretations of the question in an attempt to reconcile my understanding of work with what the book says? I'm just now learning...
Back
Top