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2( )Ministerul Educa iei Tineretului i Sportului al Republici Moldova

Universitatea Tehnic a Moldovei

Catedra: Rezisten a materialelor

Lucrarea grafic de calcul nr.3

Tema: Caracteristicile geometrice ale figurii plane

A ndeplinit:st. gr.

TCM-151

Constantin

Garabagiu

A verifcat:con.

Blan !.

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C"i#inu

$%1&

'e(olvare:

y1=2a (2a+4a )

3 (a+4 a ) =

12a2

15a=0,8a yc=

y1A

1+y

2A

2y

3A

3

A1+A2A3=0,8a 5a

2+3a 8a23,5a a2

5a2+8a2a2

=2,04 a

Ix c=Ixc1

+Ixc2

Ix c3

y1yc

Ixc1=Ix1+

;

Ix1

=1,78a4

y2yc

Ix c2=Ix2+

;

2a

3

4 a

Ix

2

=

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y3yc

Ix c3=Ix3+

; Ix3=a a

3

12=0,083a4

Ixc1

=1,78a4+(0,8a2,04a)2 5a2=9,46a4

Ix c2=2,66a4

+(3a2,04a)2

8a2

=10,03a4

Ixc3

=0,083a4+(3,5a2,04a)2 a2=2,21a4

Ixc=9,46a4+10,03a42,21a4=17,08a4