, , (. 1.14).
, .
, () , , .
. 1.15, , . 1.14, . , F.
( ) . . .
F , R, . , R.
. . 1.16 R, n D.
1. 2. (. 1.17, ) , , . RA RB, Q n ( ) m. , .
. 1. ., D. , , (), D - . (. 1.17, ).
2. - - . D (. 1.18). .
S mD = 0, - q∙ 4∙1- Rc∙ 3= 0,
RC = 40/3 .
S mC = 0, - Rd∙ 3+ q∙ 4∙2= 0.
RD = 80/3 .
: S y = 0.
RD - q ∙4+ RC = 80/3 - 40 + 40/3 = 0.
.
1 - . 0 < x 1 < 1 .
Q 1 = q ∙ x 1 Qx =0 = 0, Qx =1 = 10 .
M 1 = - q ∙ x 12/2, Mx =0 = 0, Mx =1 = 5 ×,
Mx =0.5 = 1.25 ×
2- . 0< x 2<3 .
Q 2 = RC - q ∙ x 2, Qx =0 = 13.3 , Qx =3 = - 16,7 , Qm = Qx =1 = 3.33 ;
M 2 = R ∙ x 2 - q ∙ x 22/2, =0 = 0, =3 = - 5 ×.
CD Q . Q 2 = Rc - q ∙ x 0 = 0,
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0 = Rc/q = 1.33
=1,33 = 13,3∙1,33 - 10∙1,33∙0,67 = 8,89 ×.
m = =1 = 13,3∙1 - 10∙1∙0,5 = 8,3 ×
Q D (. 1.18).
AC (. 1.19), CD R. R , , CD, C . AC.
.
S mA = 0. R∙ 2 R∙ 4= 0.
R = 80/3 = 26.7 .
S mB = 0. R∙ 2+ R∙ 2= 0.
R = 13.3 .
. S y =0.
- R + R - R = - 13.3 + 26,7 - 13.3 = 0.
.
3- . 0 < x 3 < 2 .
Q 3 = Rc 13.3 .
M 3 = - Rcx 3. =0 = 0, =2 = - 26,7 ×.
4- . 0 < x 4 < 2 .
Q 4 = - R = - 13.3 .
M 4 = - Rx 4, =0 = 0, =2 = - 26,7 ×.
Q (. 1.19).
(. 1.17, , ) .
3. R R m n. (. 1.20).
, R , , R. . D D . R .
Q , . , Q n . , , . m Qm.
n m , m n (. 1.20).
4. . q , . : , , - .
Qm = q∙ (- 0,5∙1∙1/3 + 0,5∙2∙2/3) = 10 ∙ (-1/6 + 2/3)= 3.33 ,
n = q∙ (- 0,5×2×3 + 0.5×1×2/3) = 10 ∙ (-3 + 1/3)= - 26.7 ×.
Qn = q∙ (- 0,5∙1∙3 + 0,5∙1∙1/3) = 10 ∙ (-3/2 + 1/6)= - 13.3 ,
Mm = q∙ (0,5×2/3∙3 - 0.5×1×1/3) = 10 ∙ (1 - 1/6)= 8.3 ×.
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, , .
1.3. (. 1.21, ) , , . Q m n. , . d = 1,5 , = 45 , q = 6 /.
. 1. , , D D. , , , (), D D - . , (. 1.8, ).
2. - - . D (. 1.22). .
S mD = 0, - P∙ 2 d + RE∙ 3 d = 0, RE = 30 .
S mE =0, - RD∙ 3 d + P∙d = 0. RD = 15 .
:
S y = 0. RD - P + RE =15 - 45 + 30 = 0.
.
1 - . 0 < x 1 < 1,5 .
Q 1 = - R, Qx =0 = Qx =1,5 = - 30 .
M 1 = Rex 1, Mx =0 = 0, Mx =1,5 = 45 ×.
2- . 0 < x 2 <3 .
Q 2 = RD, Qx =0 = Qx =3 = 15 ;
M 2 = Rdx 2, =0 = 0, =3 = 45 ×.
Q D (. 1.22).
D (. 1.23), DE RD. RD , , D, D . D.
S mB = 0. RC∙ 2 d RD∙ 3 d = 0.
RC = 22,5 .
S m = 0. RB∙ 2 d RD∙d = 0.
RB = - 7,5 .
RB , . , RB .
. S y =0.
- RB + RC - RD = - 7,5 + 22,5 - 15 = 0.
.
3- . 0< x 3<1,5 .
Q 3 = RD, Qx =0 = Qx =1,5 = 15 .
M 3 = - RDx 3. =0 = 0, =3 = - 22,5 ×.
4- . 0 < x 4 < 3 .
Q 4 = - RB, Qx =0 = Qx =3 = - 21,5 .
M 4 = - RBx 4, =0 = 0, =3 = - 22,5 ×.
Q (. 1.23).
RB D, (. 1.24). , .
5- . 0 < x 5 < 6 .
Q 5 = q∙x 5 - RB,
Qx =0 = - 7, ∙ 5 , Qx =6 = 28,5 ,
M 5 = RB∙x 5 - q∙x 2/2,
=0=0, =3=-4,5 ×,
=6=-63 ×.
Q 5- , 0, :
Q 5 = q∙x 0 - RB = 0,
0 = 7,5/6 = 1,25 .
=1,25 = 4,7 ×.
Q . 1.24.
(. 1.21, , ) .
3. RA RC m n (. 1 25). .
, R , , R. , , . R. R (. 1.25,).
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Q , . Q m (. 1.25, ). , , . n Qn (. 1.25, )
m n , m n (. 1.25, , ).
4. . , q , q. : , , , - .
Qm = - P∙ 0,167 + q∙ 12 d = - 7,5 + 18 = 10,5 ,
m = ∙d /3 - q (0,5×2 d ×2 d) = 22,5 - 27 = - 4,5 ×.
Qn = - P∙ 2/3 = - 30 ( n, .. Qn).
Mn = P∙ 2 d /3 = 45 ×.
, , .