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2. A 15kg block is released from rest at point A in Figure. The track is frictio

ID: 1791510 • Letter: 2

Question

2. A 15kg block is released from rest at point A in Figure. The track is frictionless except for the portion between points B and C, which has a length of 6.0m. The block travels down the track, hits a spring of force constant 2000N/m, and compresses the spring 0.25m from its equilibrium position before coming to rest momentarily. Determine the coefficient of kinetic friction between the block and the rough surface between B and O Draw the tank of energy. 3.00 m 6.00 m OCengage Learning All Rights Reserved

Explanation / Answer

at point A

initial potential Ugi = m*g*hA

initial kinetic energy Ki = 0


inital elastic potential energy stored in spring Uei = 0

after coming momentarily rest

final potential Ugf = 0

final kinetic energy Kf = 0

final elastic potential energy stored in spring Uef = (1/2)*k*x^2


from A to B


work done by friction Wf = -uk*m*g*BC

from work energy relation

Wtotal = change in KE

Wg + We + Wf = Kf - Ki

Ugi - Ugf + Uei - Uef - uk*m*g*BC = 0

m*g*hA - (1/2)*k*x^2 - uk*m*g*BC = 0

(15*9.8*3) - ((1/2)*2000*0.25^2) - (uk*15*9.81*6) = 0

uk = 0.428 <<<----------ANSWER