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#Mechanics
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A- Kinematics of particles (t,n & r,0)Problem #1
An outdoor track is
constant rate from 4
acceleration of the
o8 disla^q. Bc, rn
4 co\(ton'r{b
T\5vf= vo
utq =16
4r. =
eqhh,o'^t u P rnotuon
L + 2aras
t ? q!* 3u'
o,55 * /sec'
130 m in diameter. A runner increases her speed at ato'7 mls over a distance of 30 m. Determine the totar
runner ',2l'after she begins to increase her speed.
vo* t{*{secV$ - ? rnf s6c
E%
?
T Vo=
t=h ynlrec
ZTLC
Vg = vu4 AttUP , t( + or$[{ L'-*;" t
\vP ' 6,t m,/ set-i
.? t^[L = Dr \\ rt\4 \eL
-(6,t12 - oA nlsc*-\.._
-1A rou.l I =
rV ont 4 rgr t t/ o,fcz+ <.,,qt = 0, ( ?'l * / Sec'
b,tn-r - q.Sl. = Z6,oLo di-t-h \t.OrA
An= yLY 6si
7C-nt*-
-L
(nt
Problem #2
Coal is discharged from the tailga!" pr a dump truck with an initial velocityY n = 2 m/s at an angle of 500 with the horizontal. Determine the radius ofcurvature of the trajectory described by the coal (a) at point A, (b) at thepoint of the trajectory 1 m below point A.o8 4+ ?ovn4 A VA = ?-^ lsec .
3 Srn tLr:
1 ?t 4 Sr,,,r\ro"
orvr = uL
u,?Yut
arr*-,rr{tno
cru An:
*- Q.Q> lx (vnuto =
i| 't\"/ /' ^'r= o,6J\ rn
2t7
,VA
yxltt? r'o- u,o
)sY"
=hoL
?(,ol*uqv"o,p J." I vhzr is ?roj( Ct\L vrr.,tr_n
x -- -5a" V rt : Zrn / SCC. ^Aat gg =*1 Yn Trurd
oBuP --
-1, -V. gos
L=
! \b Sr"nq L-
2 en^-6o tL, tl,(32 to'?'Ll6 Sec_ ,
-ltablz-
-llz* q,t\ Lz
-t =a
VB ='3
4-
Vo Sun4 - Cb
2x sva -5t - 3,9\+ o,3?16
-ul, (94 ml set-3-
ob VP*,= .lq &rry : z cos-F".. _ \.zgs r,, lsec_
1gr
.fon - t
rf.8 LVPI = ,l u*rtvrr V( \r?(t
= ,n,i,Grr;;I6;, r, L ? ,
-c tt,G6 'nlftc t h'61? :- rl5
-gq + p- 15,33'I,t{S
h'\4= 3'( t* Srn .t6,3o e,(6 _r(11'.. ,
3 s* \j.3 "fivr : \zF
Problem #3
The oscillation of rod oA about o is defined by the relatio nV = uratri" r,where 0 and t arc exptessed in radial_r-s and seconds, respectively. coilDslides along the rod so that its distance from O ist-;= 16 fi; ; al .^lho.o v qnADrruED arulg rne roo so tnat lts dlstance from o isfi= 16/(t i 6)1 where r and tare expres sed in lqrn\and [s-econds'1 re specti vely. Wbggc,lj derermine (a)the velocity-.of th.e collar , (b1 thea'cceleration bf th"
"qll3f, (c),the
acceleration of the collar relative to the rod.
ry O=({l-.) (vrnrtL
A = L{ Costt L0- = - tt'Ct fyi^ -rtL
Al 1 tvrE tl-Sec
*\4o
to / cr +6)
\o 1l
-\" /,\q'b fzrts
Y& eo
+ toll * -{.,:- t'{,u I; u.r!
"1
..':(=
Y*
V eloQhr _ sAfLr-\o l,^g
{e-r4.g
Y=
Y=
l-
$=9=o-
-(Y' t\') {,
t--
= \ \r -:_"
-l /A-l w
l-\ 3qr
+
(_,
(",
t'
ac&Jrao\*r. .Zr nr€ Jt-r + Lrtg +zi'd ) {*
-'Lza. & + \,6:z
+ (u11 *o + Z+-lol,4"s*-q) &
-4-
= ; = 'hlZlZ ,r,r'/ SCc
0, O <3 vrnvtntls
Q"9
acklfia*bn "f c.dtorr rts\atw * {o vc d
Vg[,outr., {nAA rff-'- -'r ''-'J - y(*t' * [ry)' = 6'-7ta ^"' /sec
hm-l t4,/r-'-r-{ -+ .p = Z,oVSo
to/qg I
ACful-ua.fi"n r*qt = ,f-_J V '0,'lq2 I \,63t-2 : 22.8Vtt t* /(t
1a*-\ !,(rr- :5 X= \l,o3so.Zzns
Problem #4
To study the performance of a race car, a high-speed motion-picture camerais positioned at point A. The camera is mounted on a mechanism whichpermits it to record the motion of the car as the car travels on straightawayBC- Determine the speed of the car in terms of b, e. and o.
od) C.or" fywe I s 1i^\ I+ lrnro"o'iilc- b/us, = tlc"soft
%u !. = i tbl = *btc"sol-t g"
& q'-strotcos $)- J
V= :tsl s**" {-
(ps s) z
\ vt ..- -:-=I t"r g'ir^r V3s,
rf-o5 $J * 6So'
!, .- g' 9oCo\o,
b6 f ----€!i "to"ntd' I l,
COSO
= [ro'(,5 Ld
-5-
Problem #5
Determine the magnitude of theProb(4) in terms of b, e, o. and 6.
?r: b , r
coss Y -- be srr. g
tostg
acceleration of the race car of
{g*r i :ut*,*"'' ';
;l= | .t --DLg slnd
&s
+BtcosOl C,or ?O
L LCnsd ) Gsvrnu ) d
i,O t ed
t---bgtrnoc,os?g+bgto,=, -r -r\- nL^ nt tfJd Sr4n4
Lotto
Ar-= V _v-6L
hg
S-.* o Coslo + b d1 w(a (
C,o stgr ,,),Lv3g
t-o5CI
bp su,.o&s$ +
,,tbd I,n*cl
$"
+ + tr.,iro )
. ,1' r,.|
1,rsz+ bdl-(h^rd _h{
+ Tis t;u)a _L
-
tc_osc,
Cotc"
z bdsw,u(r\ ?-d .
/ffi. r rZ2 krQ Svnd
C,trlZs+ f hg SYvro coto,\
tqtu.f t d's# oJ'
n?)
Iffi
A \,\,^ -
B - Kinetics of particles.
(qt
A tractor-trailer is traveling at 90 km/h when the driver applies his brakes.Knowing that the braking forces of the tractor and the trailer are 16 kN and60 kN, respectively' determine (a) the distance traveled by the tractor-trailerbefore it comes to 4 stp-p, (b) the horizontal component of the force in thehitch between the tractor and the trailer while they are slowing down.o6 h&rO distqryr& *vo,.rcter)ftb ,^Jh"\e L45 ,u g 7ti{tt} t<{:
ly,,h{ dh'u hu,ig 6c oyrc .'].],lrt i'r
r*,,^;,i1,' J)", r#:;:ryffry-ffi': r r
P., idv-on r r r rcY (Q'c oF
ry ffiVo.furhrr^ /h s 25 urr lStC
t{vttv*-*-.1" l--? meo& tfr, -mA 6'nM# t I 'rrlq u(=.,
Problem #6
*Tg*ts3 N =.
A = -5.11
t^Jitq^^ -t tto
LUt "mt1
It{l ob* hm/st
'161ur,+ 19",-)-{ t,gl
t&i,rt"wr"qrhh (4tt&to\\og u&Io.otun co4 !hh",4 WC\
v(' * Vut + ?a asC -- GE) 2 -r t{ -s,l:l )
A E : ,lis pfu O,^ar\+
ibt z bo[r,us \la^p dottlt, n 4tn efri+
rul-.d 'l* itru ,i o\^{ huJ* ,-, g1uovr.
-*-+ fl\ A
F
V"drwt*, trc^"
w 0 S1"df P^r.{
Synes tu" ,a hils
a- *5,1?
b"Sf w,:\/ gi wt'-it^-7 -ntl!t"
(8q, r)
.% ho'n+ o.\st, mo{e(,^l,lt^ A= - E,la^/\r.
-- 7F1=o F_\6+1"3 = rnq
(= \(*ro1 - cgoo,rF S,\?
F= : l:t(6 N
bAa6rrl*vr{q d ln n6"r,to.{ L,rrn4"warrrf \9r s6 rJ,
Problem #7
2 9!^*r\ t '
Xc+Xrs = Cbrrtto**
Vc= -VglAc= -ARr-+ rD
la (n + jXe.- con $rr^{
YA= -iVe\ Aq= -jfie -*+(,,
II
Fi*rd fu'nt
\tu.,
t(q \c
til11ri*.ilritl
a;,:l
ii
aTc
,ll
Y,-\o.
',|.,"'
il.c
N
,::ni-'iiili-1:=illl.r\l:_:.?,iN
13.5 N ,
Dg
113, S
?* tool5
n -TR
gI: \.3a 46
tu loods ft
\'"t'( v - TR :- 6.r,tS$ o\ qvlurr dls c
i u' LV -Tc = o ,[,\ \?, aq-
tn\44
: 13,5 _ t,31 A s
: t{,S - o,t{S'b A4
= L4. ! - u'\At'Z' 6rt
f\O 'S [a + lc -+ 3| ---llR-a_,'
*\Jrr\et
U
tt'l-*-f ' 'l
Itjs
q,J M
-oo -flB
Tn
T..
fnrg = \,jac vtg.
fnp, .=- p,ut S?vt4
{\A a = o,tt \(? l(a
The system shown is initially at rest. Neglecting the masses of the pulleysand the effect of friction in the pulleys, determin e (a) the acceleration ofeach block, (b) the tension in each cable.
- Ldg hq^Je -) u*lives Ccatr"gls)
aln -at46
. ,TA,ltl::ll=i ,
t''
:ill:" : i '-
-+-'' l.l***
1
I
| ^r^J""-*-
:r$\i:,!
1.5 N
\,Yr, lnAM -zavo
ftol--/H
\4,S V
--+t*:
-8-
gub {\ r{nfu. UJ, in 'i
\3. S l.3J 4a -S(ur, S -o,tts10n)+,n.\ - o,uft qr
\N\! b , (b
r\,<- t,?10c, = -o,US% tt:or+_+ec )_ _\),US? [_Ou_1.g)
-Q,S [,3JAK-* t4,St0.G
-t-{.t =--r5.33 ftc
As--o!?Se *lseChc
.4n = a.2,,ZGun / seL ,
-fK
Tn
TC
(,u
Problem #8
A single wire ACB passes through a ring at c that is attached to a 5_kgsphere which revolves at a constant speed v in the horizontal circle shown.Knowing that 0, =500 and d = 0.8 m and that the tension in both portions ofthe wire is 34 N; determine (a) the angle 0r, (b) the speed u.
ivr brnoryno4 tllicctLv,E-oB 2 Fa :o
T q( gt t Tras$z _yy\3 : o
3q* Co S5r-, * 3ct* C1tgz : 5*?,6\
Co ENz _
''""
['-*k';.,
't*uf lTcoJdr:,&. r + Iuolcse!"
Tfyr,o,+Il*oi' l,-"' 'ir'"') '
, "l;1' j
. Ay,r
\,
;i** mJ
I
Norvna,t d ire c*vnn t"
Zfh - yyl Av1
( Etnpr * Snu r-) = 6*
+ [ su 6u + [vn3{,qi&)
?,?3: V2/B
\oz=0,-I9tq
36,g6"!
g,# 1 =..
! ig ?
*--fr#* pr
rtonnaz
(bl in
t- ttr' I
V2K
\J2
€
V=
v={
ttn"e"
9 , z?4( \,61_.oz d
t 3.4at '^"./ sec
tAl( ilr'n 4 hrra-ru C\ptaqr'-*4]Dr ,ht"ti tt. ,11n v^t(tt \o'|a{ldh
-taruor
r.- @,q -*o,\A3 jJ
r-,, =d
= \,620?m
-9 -
Problem #9nil
ovtru-d {" 1 {*'',1trtf eqrydirh
During a hammer thropzer's practice swings, the 3.6 N head A of the hammerrevolves at a qons1Qglbg:ec|J in a horizontul circle as shown .If p= 915 mmand 0=60", determine (a) the tension in wire BC, (b) the speed of thehammer's head.
'l0d ln brvtorrnol direql*,,YA 0\/n - 3. C = o,j61 w
t,qr\
€ {,o ="s wo rvlotion in rtI Srh Or _
T=mnSYn'cl
ouo in Mlvr,*o.l { rr g Chcn
{(6 * yy\Arr
Tcaso r. o,J 6? b+ V ?-_
P\- Co[o * tr r4.l s 6:r co: (o* = 'l,E "*/scc
"5 -w
5,(>
--S t'n(o
\ ,\s6t N ,Jfnrp,
fi o'S\S
o'1 6:1 D.j(4
-10-
rv\ h/ln -=. U- - V.trgut r4Ce,ql
A 40'5 N wrecking ball B is attached to a l2-m-long steel cable AB andswings in the vertical arc shown. Determine the tension in the cable (a) at thetop c of the swing, where 0 = 300, (b) at the bottom D of the swing wherethe speed of B is 561 cmls.
oB +h,t, is a ve{4ilal c^yu^l^a, wL-lhn
,"-.---*.--1't\2 - )^, - ?_ot C\_ coss)
T= mt L - ?4r rn3 * 3rng CoSO.
(41 oB
Problem #10
ffiffiffint end
CI=LlL
AL=
e
-AgvZ?v
It\ .?^r,*JslJ..t:
ttu, S S
( ' *-.-
t:
s li-i)-W
V-- o O = ?(j,
I t- v?7r1
t t- v?rrl
T_ ut,t?3{ * uq,6l * lt t \- Wzl ?q+ tto, S + 3*(a'u,I x V3L
= V 5,oa4.
\a
A/
(bl ftf b O=o V= 6,6i .n /sec'i
,564 -,'tz - -ZaxJ+-:-
tn1&LE$I -zK r,4.o,s
Lr-
utZ, ( sot ,V ,
l= *3x
- ll