− − − 3 1 1 0 2 2 5 1 1 0 4 3 3 2 0 1 1 1 0 2 5 1 0 4 3 ) 1 )( 3 ( 3 1 0 2 5 1 1 4 3 ) 1 ( 2 0 3 1 1 2 2 5 1 0 4 ) 1 ( 1 4 1 3 1 1 1 − − − + − − − + + − − + + + Solution 20.11 04 Intro to Eng. Analysis, Studio version Fall 1998 – Test #Friday !ov. ", 1998 Instrutions$ "0%&in ti&e li&it. ' ou an use (a)le to do t*e )ro+le&s and *eyour ans-ers, +ut learly s*o- your setu) and solution or ea* )ro+le& on t*e test )ages – read each problem to see what we want specifically . 1. /10 )ointsUsing the cofactor method, show us the setu p of your method to find t he determinant of the following 4 4 matri! "ind the numerical #alu e of the determinant$ y ou may do the determinants of any 3 3 matrices using %aple! Using the cofactor method and using row one as the &pi#ot' row, we ha#e1(1)(35) * 0 * 2(1)(+2 ) * (3)(1)(13) 1-. 2. /20 )oints/ person wearing a 5 lalloween mason his . lhead is ending o#er at the waist to picup some candy ! /ssume that center of gra#ity of the total weight of the masand head is located at a point in space with coordinates (1, 2, +) ft! he weight can e assumed to act along the ais, which is oriented #ertically ! (a) ompute the moment of the mas6s and head6s weight aou t the point A(0!5, 1, 3) ft, which is located in the person6s lower ac! F13 lr(1,2,+) ft 7 (0!5,1,3) ft r0!5 i* 1* 3 ft (/rF(0!5 i* 1* 3 ft) (13 l) ( /13 ftli* +!5 ftl() 8rite d own the e9ui# alent system t hat would ei st at point Ain the person6s lower acif we are :ust considering the weight of the masand head! he e9ui#alent system is comprised of the resultant force and moment! 1
