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Circular motion with an angle

  • #1
1. Homework Statement
the question is to find the angle that should be banked on a highway curve. the velocity is given, which is 100km/hr and the radius is 300m


2. Homework Equations



3. The Attempt at a Solution
i know i need to convert the units first, but then i dont know what to do... to find the angle, i need to use tangent to find it, or is it?? if yes, i dont know how...
plz help...tmr is the physics final...thx a lot~~XDXD
 

Answers and Replies

  • #2
1,860
0
I can't remember if you end up getting a tangent or not, though you will probably end up with tan or cot. If you draw a careful freebody diagram, and use Newton's 2nd law properly then you can get through this problem.
 
  • #3
the equation i got is that [tex]\tan\theta=\frac{v^2}{rg}[/tex]. i dont know how i got this equation, but it did give me a right answer. can u help explain it?
 
Last edited:
  • #4
98
0
I think you end up with mgsin0 = mv^2/r
0 = theta

if you draw a freebody diagram you should see that it is that component which creates circular motion. if i'm wrong i apologize but i'm 85% sure. :P
 
  • #5
no...it should be tan, coz i got the right answer from my equation. i just dont understand how i can get the equation on #3
 
  • #6
98
0
i think it depends on where you're counting the angle from.

draw a freebody diagram of the vehicle on the banked turn, the perpendicular component to the car's motion is the Fc. you can write it in terms of Fg and an angle.
 
  • #7
cristo
Staff Emeritus
Science Advisor
8,056
72
Where did you get the equation in post 3 from then? What concepts should you use for this question? From these concepts can you attempt to derive the equation?
 

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