637_Dynamics 11ed Manual

637_Dynamics 11ed Manual - d = 2 96.6 rad s = *Problem 19-8...

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Engineering Mechanics - Dynamics Chapter 19 0 A y t 1 + m w gt 1 0 = A y m w g = A y 98.10 N = Problem 19-7 Disk D of weight W is subjected to counterclockwise moment M = bt. Determine the angular velocity of the disk at time t 2 after the moment is applied. Due to the spring the plate P exerts constant force P on the disk. The coefficients of static and kinetic friction between the disk and the plate are μ s and k respectively. Hint : First find the time needed to start the disk rotating. Given: W 10 lb = s 0.3 = b 10 lb ft s = k 0.2 = t 2 2s = r 0.5 ft = P 100lb = g 32.2 ft s 2 = Solution: When motion begins bt 1 s Pr = t 1 s Pr b = t 1 1.50 s = At a later time we have 0 t 1 t 2 t bt k Pr () d + W g r 2 2 ω 2 = 2 2 g Wr 2 t 1 t 2 t bt k Pr ()
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Unformatted text preview: d = 2 96.6 rad s = *Problem 19-8 The cord is wrapped around the inner core of the spool. If block B of weight W B is suspended from the cord and released from rest, determine the spools angular velocity when t = t 1 . Neglect the mass of the cord. The spool has weight W S and the radius of gyration about the axle A is k A . Solve the problem in two ways, first by considering the system consisting of the block and spool, and then by considering the block and spool separately. Given: W B 5 lb = 635...
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