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Unformatted text preview: ,‘ ' The tensxon t‘orce T! in the cable BC has a L/Kcrw l—c ‘K‘IWMA Q"! PROBLEM #1 Given: A force of 10kN is applied at F to the mast
which is supported by two cables BC and ED. magnitude of lSkN. Find:
a) The force I! applied by the cable at BC. on the mast at B in terms of its xvz components.
I, = 5&  21145 KN
b) The magnitude of the projection or force 0 II along the line AC. «rucc‘: 5.395 RN c; The moment of the lOkN force about the pointD. Mb: 602, 905 RNm ’X . d) The magnitude of the moment of the lOkN t'orcc along the line AD. MA) :. 5—642. kN m PROBLEM #2 Given: Three t'orces and a couple acring on
a Lshaped bracket shown. Find: a) The equivalent forcecouple syStem at the base D of the bracket. 5: 25’5' 4 .4: b) The resultant of the three forces and the on the yaxis through which the resultant _
mustpass. E : .24(,. 4 93504  NOTE: Drawing appropriate tigures is important.
PROBLEM #3 Given: A bracket and pulley assembly weighs 85 lbs
with the combined center of gravity at G. A force of 100 lb is applied to the cable end which goes over the pulley at B. The
other end of the cable is attached at D on the vertical line AC. Find: The reactions of the pin at C on the
bracket. Express the result in vector torm. Q = — “{6 6i; ‘4' I'H‘é Why is the result independent ot‘ the
Iocatton ot‘ the attacnment pomt D'.’ ' 35.0! Nagt M 
Couple. and the ycoordinate of the point ‘5‘ [332‘ gig" ISBN _ .2 3P:—oozgm a." SPRING 1942. PROBLEM #1 Given:
Ttvo forces E, and E, are as shown. The force El has a
magnitude of 150 lbs. The force 5, is given by E, =—lOOi_—65j_lb. F ind: a) The force E‘ . expressed as a vector in terms
of the x y z coordinate syStem shown. The directiOn angles of the force E.
a) The moment of force E, about the point D. The magnitude of the moment of E, about \
the line AD. 4) fl :me; + 104251. ~72~I5 5 lbs b) 8,317" 9y 1450 J Ba : //8.8°
c) [13 = 533‘; +900; +13”); [5 in 4) )H
 — “Ab
PROBLEM?” PART A (3 pts.) Given: 3 lbft. Find: The cquipollent force and couple :1! O. F=3klb _r~ ._ J M = ‘0 l
The 3 lb force at A and the couple of magnitude {47‘ PART B (12 ms.) Given: One 50 Nforce. a uismbuted load. and a 500 Nm
mutate acung on me memoer ABC. Find: I l\ .1) 'th SlmplCSI resultant wmcn 15 a smgtc tome. and 1 6 m. b) The pomt on the x‘axis through which the line of I i _
tction of the smgic force in (:1) must pass. ‘ 39 N a) Er: "Emit5‘04; M b) Anamevm Ea mugged/3‘. PROBLEM #3 Given:
A uniform bar weighing 60 lbs rests in a horizontal
position againSt two smooth inclined surfaces. A con ccnmtcd vertical load of 200 lbs acts at ti .distance x
from the end B of the bar. The bar is in cquutbnum. Find: 1; The mazmtudcs of reactions at A and B. b) The disumce x. 4) Nb: tagNb than.er 5) 7L: 1.44 18t— PAL; 32 6:9. ~
w
PROBLEM #1
Given: Two t'orces E. and E. are as shown. The force 5.. along the line joining points 0 and E. has a magm
‘tude or 150 N. The force E. is given by E\=izoj_+aogN. Find: a) The vector expresston for E, in terms of the x y z
coordinate system. b) The direcoon angles of the force 13‘.
c) The angle between the forces El and E). d) The moment of force Ed about point C. PROBLEM #2 Given: Three forces and a couple g act on a box as shown.
The coupie Q has a magnitude of 200 lbft and its direction is perpendicular to the shaded plane
OED.asshown. Find: a) An expression for the couple (_: as a vector. in
terms of the unit vecmgiand l_t_. b) A force at B and a couple. equipollent to the given
system of forces and couples. c2 Can the given system of forces and couples be /
reduced to an equtpoilent Single force? You need A A A
to give appropriate mathematical argument to x a.) Q : €971 ‘l336’ +(33k (’5' Ft obtain complete credit. 5) frz—KO'O44+/U'Df+5‘02 [b
A
PROBLEM” g (lib:— 6672133f66'7k M3147 Given: LM Lt. red uncut 1’0 A
The bent rod AB is supported at B by a pin joint. _ and at A by a roller resung on an inclined plane.
The rod is subjected to a force of 390 lb. a couple
of magnitude 300 lbft. and is in equtlibriurn.
Neglec: the weight of the bar. Find:
:1) Draw the freebody diagram of the rod. b) The reactions at the toiletA and at the pin 8. 6) ’VA .2 /0S"/ lb
§197'9t4+a2687; £5 #6? 270  ark/9me E'Xﬂvﬂvanuuf tt/ Name (Print) 50 C U770 NS
Instructor
ME 270
EXAMINATION #1 THURSDAY, FEBRUARY 18, 1999 PROBLEM #1 Given: The rod shown is supported by two brackets
at A and B. ' Z Find: (a) The moment about the line from A to B.
MAB. produced by force F of magnitude 1?] = 1000 N. (The line of action of force F is from C to D.) (b) What is the angle between the line of
action of force F and the yaxis?
Use the vector approach! (Q) 17— = " ) '_  F— " 0 2 "
4 3/5 F / % J
Ié‘: (coo '— = F _. / 0'6r‘0'3r‘0'2.‘ = — ..
can a,” ‘T.’(‘ " "a in.“ .L 0.07 I 0.0Y gnu 1q’g‘ h, F
I? l7 1" ) MI
2 /   ~ —
A an a ' [7 = .e" — . . _ I? . Iy~ A
/ .— ”" U %)e"“” 2% {73‘ '1ﬁ”*mmf
’74,; " Mw~ “I Q’Wr Hm r ~59; 1‘) (Mr) = (“"Xm) cus Gu 5‘22
0 c. a. $49.2" /: a: n.3’. ﬂ”? '7' ‘37?”W ‘0‘ A Mate as: IF you m~ Sﬂaw mm— A 6160344 We»:
4: 52’?! MW 3’0 IPN Meir/ow on A “Mega .me‘sr OF P4ng 4' 2»
av an I 
rt "tremor: m , be at» 453 7.1.;qu 0‘ Mum, "F 9M,“ “0*?!ka 0F A warm aF mac"; n," RP (PM “N F“? m km waif“: ?. , ‘
TH! Alanna; e4 Pomtr Jame") MINNVIDUM mm on FIS'HL'IPJ 0F M1“
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Rtrumv 0P r»? emu! WM ME 270 EXAMINATION #1 Name
February l8. l999 IPrinti [Lusti iFirsti PROBLEM #2 Given: The streetlights at A and B are suspended
from the two poles at the same height of l8 ft.
[feach light has a weight of 50 lb, determine
the tension in each of the three supporting
cables and the height 12 of the pole DE. ﬁnd: T <9 7‘ M 7‘
A 7' c
D 4 ac qty].
‘qaf: I.
SOIL
rigo
733.940 :0 no
{6:0
"7;DC°I9F;ao 7;: 7:0 = fan any)”: 570 "
w
.— ro __ .. It
7;» ‘ Enra’wi ‘7‘ /' i?” ' 40F" / 4 = 23 a4
PROBLEM #3 Given: The beam shown is pinconnected at A
and rests against a frictionless roller at B.
The beam is subject to a force F = 60 N.
and a couple M = 75 Nm applied at C. Find: The reaction force vector X from the pin. f) 2);, =0 I —;,..F(,) —U(A7r)=o/ 4v: /}bM o A
TF=O _ largo‘4 =9 .A =M.a.;1u:(¢vﬁ,,7 g 1 F
=3 A
{F}, 20 I‘ I/QJJQ.II? F=o/ 6,:F— ﬁlmm' N ,
— “mewno = 4:2” ,9 : for .i. air7.54: w 5 9c \rE °\‘5
PROBLEM # L: Given: A Gambrel roof truss ABCDEFGH supports the forces shown in the figure
At A, the truss is supported by a roller, and at H, the truss is supported by a pin joint. Find: H
a) The reaction forces acting on the truss at points A and )1; write these forces as
vectors; b) The forces in the members BC, CE and BD;
c) Clearly state the nature of forces in the members BC, CE and BD, that is, are the l . . . .
members 1n tensron or 1n compressmn. v“. = \acxz. MA
Rx): "\38 k R #2: For the truss shown below:
a) Identify ALL of the zeroload members. V
b) Determine the load carried by members HI, CH and BC. :5: = E = MM‘A
RC = $000\\b(c\ ...
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 Summer '08
 MURPHY
 Force, equtpoilent Single force

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