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Homework Help: Simple Normal/Tangential Acceleration Confirmation Needed

  1. Oct 18, 2011 #1
    Hi guys,

    Got an exam this afternoon, and really need help with this. I think I'm right, but I just need verification and explanation.

    1. The problem statement, all variables and given/known data

    A car rounds a bend with a radius of 200m. At a particular instant, the car has a velocity of 60km/h. The speed of the car is increasing at a rate of 5m/s^2. Determine:

    i) the normal and tangential components of the acceleration of the car
    ii) the magnitude and direction of the resultant acceleration
    iii) how far around the ben dthe car will travel before v=20m/s

    2. Relevant equations
    at = the rate at which v increases, given as 5m/s^2 in the question.
    an = v^2/r

    3. The attempt at a solution
    My solutions:
    i) an=v^2/r=((60/3.6)^2)/(200) = 1.38m/s^2
    at = 5m/s^2

    ii) |a| = sqrt(1.38^2+5^2) = 5.186m/s^2
    theta = tan^-1(an/at) = tan^-1(1.38/5) = 15.43 degrees

    iii) No idea. Really need help with this one.

    Are i and ii correct? Help with iii appreciated also. Thank you so much.
    Last edited: Oct 18, 2011
  2. jcsd
  3. Oct 18, 2011 #2
    i) an=v^2/r=((60/3.6)^2)/(200) = 1.38m/s^2

    For the final part think about the equations for uniformly accelerating bodies.
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