Part |. Equilibrium of a Rigid Body. Solve the problem as indicated.
41. Determine the reactions at the supports.
SOLUTION
Equations of Equitibeiam,
‘equation of equilibrium about point B by referring 1 the FED of the beam shown,
inFiea
GEM, = 0; 8005)25) — 44) = 0
Ny ~ 383333 N = 333kN Ams
Liege rento wie fae stool ein sgt nyc
sxnne asm (?
5, = 2008 = aan me
stsp=o sss woa(!) 2-0
1333 = 133 Ams.
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2. Ifthe roller at A and the pin at B can support a load up to 4 KN and 8 KN, respectively, determine the
maximum intensity of the distributed load w, measured in kN/m, so that failure of the supports does not
‘occur.
4mSOLUTION
Equations of Equilibrium. N, can be determined directly by writing the moment
‘equation of equilibrium about poiatB by referring wo the FBD ofthe beam shown
inFiea
eX My = 0; w(4)(2) ~ Nasi 4° (3 sin. F) ~ Nicos M0 Boos + 4
Na = 123766
Using this result to write the free equation of equilibrium along + and y axes,
SX = 0) 125%6wsin— B= 0B
6188
+138, B, + 1.2376 60830" — wid) B, = 29282w
Thus,
Fy = VBE +B} = VES WF + 292K wy = 2.99290
eis required that
Fg < SKN; 299290 <8 w <2673KN/m
And
Na <4kN; 12H 6w <4 WC 3QKN/m
Thus the maximum intensity ofthe distributed load is
2.673 N/m = 2.67 KN/m Ans.
wt)
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3. The bent rod is supported at A, B, and C by smooth journal bearings, Determine the components of
teaction at the bearings ifthe rod is subjected tothe force F = 800 N. The bearings are in proper alignment
‘and exert only force reactions on the rod.SOLUTION — "|| x wom
equation of Equibriam. The xy and e components of force are
F, = 80005 60 05.0" = 641.
E
800 cas sin 30° = 200 N
= S00sin 6" = 692.
‘Rofertng tothe FRD of the beat red shown in Fi,
EG BD) RTO) o
AMO BG) + CQ) e
BM.= 0) -G(075)~ C2) ~ B11) ~ Mo1Q) = °
BR=O A+C.+3641=0 o
Bh=0 +B+6,= °
TR=0 A+B, onw2=0 o
Solving Eas (1) 106)
6, = SN B= 10718 N= 107N 8 = ON An
C,=S339N=SRON A= ADDN A, = SON Ans.
1, and A, ate directed inthe senses opposite to
‘The negative signs indicate that C,
hoe shown in FAD.
Ame
¢,= ON
= WN
B,= «oN
C= 56N
A. = 400N1. Thesmooth pipe rests against the opening atthe points of contact A, 8, and C. Determine th
‘needed to support the force of 300 N. Neglect the pipe’s thickness inthe calculation. (Answer: A~173N,
c=e16N)
SOLUTION
Equations of Equiitrium. N, can be determined direcly by writing the force equation of
esqlirium along the x axis by referring tothe FAD of the pipe shown in Fi.
SER = 0, NycoeM~ 300sin3P = 0 Ny = 17321N = 173N Ans
Using this resto write the moment equations of equilibrium about points B and C.
GHEMy = 0; 300 0830°(1) ~ 17821 cor 307026) ~ 17321 sin 37(015) ~ Ne(OS) = 0
Ne= 41363 = 416N Aas.
GhEMe = 0; 300.60830°(05) ~ 17321 c08 37(026) ~ 17321 sin 37(045) ~ N4(05)
Np = 6820 = 692N
Ne’ 020m
05m osm en
Jou Ne
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reactions at these points12. The member's supported by a square rod which fits Loosely through the smooth square hole ofthe attached collar at
‘Aand by a roller at 8. Determine the components of reaction at these supports when the member is subjected tothe
loading shown (Ansiver: Ax=300N, Ay=500N, Nb=400N, Mie TkN-m, My=200N-m, Mz=1.SkN-m)
oN
‘SOLUTION
Farce And Potion Vectors. Ths coordinates of point and Care wT gos
BOAO) and etd 2m aby
= + nj ~ sau
Ma = (Mah + (ad ~ (Me
ay Nm tyo = 28
Equation af gl
forveequnton oem
(300 — A+ (500 A + (Ne tn) = 0Equating ij and k components,
300 ~ A,
Ans
A, = S00N Ams.
Ans.
Ny = 400N
‘The moment equation of equilibrium gives
EM, = 0; Ma + tan Nu + tac x F=0
pep deg &
(Mit (di (dar i2 0 of+]3 0 -2]=0
0 0 4001 300 suo -400
[1000 — (ta), Ji + [(Ma), — 200]j + [1500 - (,)_ Jk = 0
Equating i,j and k components,
1000 — (My) = 0 (Ma), = 1000N-m = 1.00 kN-m
(a), ~ 200=0 (My), = 200N-m
1500 ~ (My), = 0 (My): = 1500.N-m = 150 kN-m
FRE
sa.
“The bulkhead AD is sbjecte to both water and sil
teekfil premures Asuming AD i “planed” 10 the
found MA, determine the borzon
SOLUTION
yeas of ivi Teo wn BC he ine ety
GEM, = 0 tOIrS(2A167) ~ 2361388) ~ £6)
F = 31398 N = 11N Am
ARR<0 | A,+ 31S +2%6—10nS=0
A, = 460K Ams
TEER @ A780 4, ~ TASK AmsPart. Stuctural Analysis. Solve the problem as indicated.
1. Determine the force in each member ofthe uss and state f the members are in tension oF
‘compression, (Hint: Use Method of Joints)
Skip
1 weave
SOLUTION
Ay(40) + 15(4) +202) — 140) — 300) = 0A, = 1Sp
1842-£,=0 £,=35kip
Bt1s-3-320 6, =45Kip
Fy AM9EIp ~ 404kIP ©) ‘Ans.
Pay = 4089062190" =O yy = 27ST) Am
45 — Fey sin 2.80" ~ 0
Fup ~ LID ~ 2Lkip(C) Ans.
REP. = 0 Pup 35 + LIDeo 218-0
Fen = 195K9 (1) Ans.
Join
2184, <1 Py <0 Am
EFL 0 Fag 3980 Pye = 395 ip (1) Am.
soins >
itor, =o Foe=0 Ans.
EPA Orie RISO Fue = TIS KPT Am
Fyceus 4640" ~ 3052180" =0
Fre = AUB kip = 414 kip(C) Am.
SABES =O Bag + Sen 21M + 40sinabaE — 1D =a
Fig = 8UTBkip = 808% (C) Ans.
Jon
SEA G2 Foci 0
Fryg = 2454
215k) Am
21S n 21ND ~ Fy = 0 Fy = SIP ET) am2. Determine the force in members BC, CH, GH, and CG ofthe truss and state ifthe members are in tension
‘or compression.
SKN
SOLUTION
Sepport Reectiom. Referring to the FID ofthe entre truss shown in Fg, A, can
te determined dicey by writing the moment equation of equilibrium about point F
CABMy = 0: Sid) +818) +4112) ~ A(16) = 0A, = 825KN
3K, Ano
Method of Sections. Referring to the FID of the let portion of the truss section
Utwough aa shown in Fig, Rye, Fy ad Rey can be determined diecly by writing
‘the moment equations of equilibrium about points H, Cand O, respectively,
G48My =O; Facl3) ~ 82568) =O Fe = 1.ORN (TY Ans
came Fale) 9 +c - 1288-0
Fay = SV KN (C) = 11.2 kN (C) Ans,
ety = 0: fn(2)u0 + 252)
0 fey =1284N(0) Am
Meet di Ui te lh Fan aim ft eis
san=0 (5V5)(2)~to(2)=0 tur= (sv8)anco
sty 5V9) 2) teo= 0 Fee a0 even
Ans
Fae = WORNCT)
Few = N2EN(C)
Fey = 1L2S4N(O)
Fea = 1OOKNCT)(Spssan ee nparoncen waar aurgmonae oS)
SOLUTION
Method of Jolare tn this ease, the support reactions are wot required for
determining the member forces
Joint A:
aL,
ral
va * ts
Fg ~ 6A2AN (T) = 646KN (T) Ans
2 3
Pac(3)- Fail) = 0 Fae= o
4 4
uc($) + Fal $) — oa
Frc Fan = 300 ®
Solving Bs (1) and (2) iets
Fre 0% (©) Am.
Fee Fao o
) + Fao{ $2) - sa $2)
OVS, va,
Fre + Fay = 1397 ®
Saving as (1) am) yes
ne = Fup = 3009 N (C) = 3708 (C) Am
® [san se
Va
Fae = AB0KN (7) Ans
[Note:The support reactions at supports C and D can be determined by analyzing
joints Cand De respectively using the results obtained above.
Ame
Fp = 646 KN (1)
Fre = Fan = 150 N (©)
ye = Figg = 3.70 EN (C)
Fup = 480 KN CT)3. Determine he ec inmanbers A, Fon 8, a att te memes ein aso of cameron ose
BPP OCS COPING)
o_o
SOLUTION am
Support Reactions. Not requited
“Method of Sections: Referring othe FID of the upper portion ofthe tus section
through a-a shown in Fig. a, Fyy and Fye can be determined diecly by writing the
‘moment equations of equilibrium about points B and F, respectively
AEM = 0; Fy(LS) ~ 82) - 444) = 0
Fay 2394N (1) ~ 213 KN) Am
GoEMe =O: Fah) ~ 40) =0
Fac = S33EN(©) = 533 EN (0) Ame
Aso, wit he fore eatin of ei slong the we can oan Far
area
LF = + 3). a
sansa 468 mu(2)<0 Fp ano ENco) ron
15m
2m
@ “a
4 a
m
oN TeSOLUTION |——1s0
Tic
CrsM.= e106) ama) + B,05)- asm 05)
b.wt
seamen COD
Berm ke :
a
Ne = 266 6
+12P, = 6
= n+ sta
64802 = 6091
GrEMe= 0-61) ~ 120015) + HAIL 40)
n
OU) — Me= 0
Me = ~#23138Ib+ = —423kipe
Segment Ds
ute
Ans. topo sf
2
Vo Eom =0 ON) ee
e375 Ans.