1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Physics homework problem. Please help!

  1. Nov 4, 2008 #1
    On a banked race track, the smallest circular path on which cars can move has a radius of 111 m, while the largest has a radius of 157 m, as the drawing illustrates. The height of the outer wall is 15.7 m. Find (a) the smallest and (b) the largest speed at which cars can move on this track without relying on friction.


    I am having trouble finding an answer because I wasnt given any angles. Please help me in any way that you can. Thank you VERY much!
     
  2. jcsd
  3. Nov 4, 2008 #2

    PhanthomJay

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    You didn't attach a picture, but I believe that the track is sloped at an angle that has a 15.7m rise over the track width of (157m -111m) = 46m. From that, you should be able to detremine the angle.
     
  4. Nov 4, 2008 #3
    Using that information I found the angle to be 18.85 degrees. And I found the answer to part (a) 371.38. But that answer is not correct.

    Do you know what I did wrong? Any additional help?? Thank you....
     
  5. Nov 4, 2008 #4

    hage567

    User Avatar
    Homework Helper

    Did you remember about the square root?
     
  6. Nov 4, 2008 #5

    PhanthomJay

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    your angle looks good. I didn't see your work or check out the math on my own, but you may have used the wrong component of net force in the horizontal direction. What did you use, and why?
     
  7. Nov 4, 2008 #6
    I used the equation v= sq.rt. r*g*tan (theta)

    So, my work for part a is...

    sq. rt. (111)(9.8)tan(18.85) = 371.38.

    The computer tells me that is the wrong answer...
     
  8. Nov 4, 2008 #7

    PhanthomJay

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    oh, yeah, should've done the math....take the sq root.....
     
  9. Nov 4, 2008 #8
    It worked!!! THANK YOU! I guess I did forget to take the sq rt. Thank you both.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Physics homework problem. Please help!
Loading...