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Masa, Centar mase & Moment tromosti

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MEHANIKA 3 – Laboratorijska vježba: <strong>Masa</strong>, <strong>Centar</strong> <strong>mase</strong> & <strong>Moment</strong> <strong>tromosti</strong><br />

Sl 4 „Vaganje“ grede 2<br />

Uz pomoć jednadžbi ravnoteže a na temelju izmjerenih reakcija u osloncima odredi se<br />

težina (masa) i centar <strong>mase</strong> grede (Sl 5).<br />

Jednadžbe ravnoteže:<br />

Iz kojih slijedi:<br />

Greda 1:<br />

Sl 5 Greda oslobođena od veza<br />

)<br />

)<br />

∑<br />

∑<br />

1 F = 0 : F + F − G = 0<br />

y A B<br />

2 M = 0 : F ⋅l − G ⋅ x = 0<br />

A B c<br />

G = FA + FB<br />

FB ⋅l<br />

xc<br />

=<br />

G<br />

.<br />

Izmjerene reakcije: F A = 40 N, F B = 69 N<br />

Težina je: 1 109 G = N<br />

Razmak oslonca: l = 0.5 m<br />

<strong>Centar</strong> <strong>mase</strong> duž x-osi je: x c1 = 0.316 m<br />

Greda 2:<br />

Izmjerene reakcije: F A = 24 N, F B = 34 N<br />

Težina je: G 2 = 58 N<br />

Razmak oslonca: l = 0.5 m<br />

<strong>Centar</strong> <strong>mase</strong> duž x-osi je: x c2 = 0.293m<br />

Katedra za dinamiku i vibracije – FESB 4

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