Please help to find mu, frictional force and normal force

  1. a body of 5 kg mass is resting on a board which is gradually tilted until, at an angle of 30 degrees to the horizontal, the body begins to move down the plane. find coefficient of friction and magnitude of the normal and frictional forces when the body begins to slip.

    i managed to workout Force due to weight i.e. (Fw)x = 24.52N and (Fw)y = 42.47N also the Fn(Normal force) = 42.47 but i cant workout mu(coefficient of friction) as i dont have Ff(friction force) from the formula mu = Ff/Fn
  2. jcsd
  3. tiny-tim

    tiny-tim 26,016
    Science Advisor
    Homework Helper

    welcome to pf!

    hi jaybabbar! welcome to pf! :smile:

    (have a mu: µ and try using the X2 icon just above the Reply box :wink:)
    ah, but you know that the components of force in the x direction must add to zero …

    so you know that Ff = (Fw)x :wink:
  4. The body moves at 30 degrees so you need to use trig to break it into components at that angle. The force going down the ramp must equal the frictional force at the point friction breaks. The force going into the ramp is equal to normal and using both you can find coefficient of friction.
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