the test question i had the most trouble with was:

Question

amistre64 · Answer

a car has a mass of 1500kg, and is traveling at 26.8 m/s at the top of an incline; the incline has a slope of 1/10

a) what is the Kinetic Energy?

      i did 1/2 m v^2

b) if the car coasts downhill, how fast is it going after it has descended 1000 meters?

     i tried:  $v^2=(v_o)^2+2a\Delta x$ and tried to determine the acceleration.

c)  What is the breaking force needed to maintain the initial velocity going down the hill?

     i considered:  F = ma, using the acceleration from part b)

d)  at the bottom of the hill it goes around a curve at 29 m/s; the curve has a radius of 90 meters, and the tires have a coeff of kinetic friction of .98  Does the car slide, or does it stay on the curve?

   My idea was:    Fk = uk m g ,  Fc = m ac, where ac=v^2/r

amistre64 · Answer

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