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Homework Help: Force of Object on Inclined Place

  1. Jan 26, 2004 #1
    I need extra help. I'm studying for my Final Exam which is tomorrow and I cannot remember how to find forces of objects on an inclined plane. The question I'm having troubles with is:
    A 12.5 kg crate is placed on a ramp that is at an angle of 22 degrees from the horizontal. Find the acceleration of the crate would be down the ramp:
    a) in the absence of friction (answer 3.67 m/s-squared down slope)
    b) if the coefficient of kinetic friction is 0.0 (0.95 m/s-squared down slope)
    I have tried this and I know that I need to find the force of Gravity that is parallel to the direction the box is going. But I keep getting like 347 and then an answer of like 20.0 something m/s-squared. What am I doing wrong!?!
     
  2. jcsd
  3. Jan 26, 2004 #2
    You should be doing this:
    122.5sin22 = 45.9N or 45.9kg m/s^2

    Fnet = ma
    a = Fnet/m
    a = (45.9kg m/s^2)/(12.5kg)
    a = 3.67 m/s^2
     
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