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Brake or swerve?

  1. Nov 7, 2007 #1
    My professor went over this but forgot how he explained it.

    Basically he said if you're in a car and have a wall stretching for miles ahead of you what would be better to do brake or swerve?

    He wrote something down about how cornering takes place at a rate of something and that braking takes place at another rate. He said braking was faster.

    Can anyone show me this again?

    Thanks yall!
     
  2. jcsd
  3. Nov 7, 2007 #2
    In general it is always better to break (since in real life swerving inevitably ends in hitting something else instead anyway, and at a much higher speed, plus it's unpredictable to other drivers), hence you should just drive to maintain safe breaking distance from all potential hazards.

    As the for mechanics problem, if we presume the tires can only apply a certain force (before skidding), then by directing that force exactly opposite to the car's momentum (breaking) the car will minimise the velocity at which it hits the wall. Swerving means directing that force at 45 degrees, making the anti-forward component less. (Cute problem, although its logic applies only to wide targets.)
     
    Last edited: Nov 7, 2007
  4. Nov 7, 2007 #3
    You'ld have to figure out the min radius that the car could take based on friction and speed:
    http://www.batesville.k12.in.us/Physics/PhyNet/Mechanics/Circular Motion/an_unbanked_turn.htm
    and compare that to the min braking distance in straight line.

    Its been too long since I've done this stuff, it'll be interesting for me to see solution, as well as if the initial speed or mass of car makes a difference.
     
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