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the conditions of rest or motion of bodies under the
action of forces$
- Statics - (ynamics
" Mechanics is an applied science - it is not an abstract
or pure science but does not ha)e the empiricism
found in other en%ineerin% sciences$
" Mechanics is the foundation of most en%ineerin% sciences
and is an indispensable prere*uisite to their study$
Fundamental Concepts
" Space - associated #ith the notion of the position of a
point P %i)en in
terms of three coordinates measured from a reference point or
ori%in$
" Time - definition of an e)ent re*uires specification of the
time and
position at #hich it occurred$
" Mass - used to characteri,e and compare bodies e$%$
response to
earth.s %ra)itational attraction and resistance to chan%es in
translational
motion$
" Force - represents the action of one body on another$
force is
characteri,ed by its point of application ma%nitude and direction
i$e$
a force is a )ector *uantity$
/n Ne#tonian Mechanics space time and mass are absolute
concepts
independent of each other$ Force ho#e)er is not independent of
the
other three$ 0he force actin% on a body is related to the mass of
the body
and the )ariation of its )elocity #ith time$
"umerical Accuracy
" 0he accuracy of a solution depends on 16 accuracy of the
%i)en
data and 26 accuracy of the computations performed$ 0he
solution
cannot be more accurate than the less accurate of these t#o$
" s a %eneral rule for en%ineerin% problems the data are
seldom
3no#n #ith an accuracy %reater than <$2=$ 0herefore it is
usually
appropriate to record parameters be%innin% #ith 91: #ith four
di%its
and #ith three di%its in all other cases i$e$ +<$2 lb and 1$;
lb$
" 0he use of hand calculators and computers %enerally ma3es
the
accuracy of the computations much %reater than the accuracy of
the
data$ >ence the solution accuracy is usually limited by the
data
accuracy$