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A student wants to determine the coefficients of static frictionand kinetic fric

ID: 1744474 • Letter: A

Question

A student wants to determine the coefficients of static frictionand kinetic friction between a box and a plank. She places the boxon the plank and gradually raises one end of the plank. When theangle of inclination with the horizontal reaches 30°, the box starts toslip, and it slides 2.3 m down the plankin 3.9 s at constant acceleration. (a) What is the coefficient of staticfriction?
1

(b) What is the coefficient of kinetic friction?
2 (a) What is the coefficient of staticfriction?
1

(b) What is the coefficient of kinetic friction?
2

Explanation / Answer

(a)    the coefficient of static friction is givenby    s = tan         = ......... (b)    with help of newtons second law of motion weget that    m g sin - f = m a    f = fk      = kFN      = k m gcos     with d = 2.3 m and t = 3.9 sacceleration will be    a = 2 d / t2    k = ........