Question

Homework Problem 18.39 7 of 8 A Review The spool has a mass of 56 kg and a radius of gyration ko 0280 m (Figure 1) Part A If the 21.kg block A is released from rost, determine the velocity of the block when it descends 0.6 m. Express your answer to three significant figures and include the appropriate units. HÅ Value Units Figure < 1 of 1 Submit Request Answer Provide Feedback Next > The figure shows block A moving vertically downward with reached uncoiling from the lemon point of an inner core of a spool The spool is fixed its center point. The so has a radius of 3 meters, and its inner con has the radius of 2 meter

Answer 1

Potential energy with referrence 56kg Glven dak The Sphool has mas Raslices of gylation Ko = 0-280m Block-A may = 21 kg 9:21 A "FBP) : to datum establish in FBD, the gravitational potential energy of block a are position 4. are V, - (V9), = WAGI 21x9.81XO 03 LAW - V₂ = (Vg2 -WAY2 = -21% 9-8)X0-6 Datum =-123.6J Kinetic enersy Uz=0.6m she the spool rotates about fixed El axis VA YA = 5VA 0.2 el ángular velocity w = = UA mais moment of inentia about fixed asis passes through point a To = mko

Thus, kientic energy of the System is I = 54.875 0 + 10.5 VÃ Po = 56 x 0.280 = 4.39 kg W+ PA) + 1 x2 x2lXUA I = £*4.39x (ava) 7 I= 65.37 VA since the System is initially rest T=0 Conlevation of energy - Tz + V2 Titvi 10+0 = 65.37 VĂ + (-123-6) 65.37 VA = =)23.6 123-6 = 10890 65-37 JA= 1.890 VA = 1.37 m/ see Velocity of block VA = (- 3+) a.