ΤΡΑΠΕΖΑ 2014 ΦΥΣΙΚΗ
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2014
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5259
) )
) 1 2F F F= +r r r
( ) ( )2 22 21 2F F F 4N 3N 5N= + = + =,
2FF ma a a 2,5m / sm
= = =
) B)
) .F =r
, . .
. :
t 0 =
9093
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) )
) : = ( t1) / t1 = x1/t1 (1)
x1 = 12,5cm. (1) :
(1) => = (12,5cm)/5 cm/s => = 25cm/s
) )
) (t=0) = 0 , F = Fx = F >0. , : = F/m => = F/m > 0 (1). (1) t = 0 t = t3, , , .
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) ().
) : s/m5s/m4
20
4,02
1,04
m10200
tS
111
2
1
1 ===
==
: s/m2s/m12
s1,010m10200
tS
11
2
1
2 ==
==
: 21 >
) )
) () (): UA + K = U + K = UA U = mgH mgh = mgH mgH/2 = mgH/2 K = U
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) )
) F , .
.
) A)
) : E ... :
)(.
)(.w WW == mgh2
)(. = (1)
: E ... :
)Z(.
)H(.w WW == mgh2
)H(. = (2)
(1), (2): BA)H( .)( . KK ==
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1wr
1Nr
Tr
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) )
) :
SSS 21 ==
212
1
)1(
)2(
2
1
)2(
2
)1(
1
2
1
)2(
22
)1(
11
154
tStS
tS
tS
tS
tS
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) )
) , .
) )
) . t=1s
t=0 t=1s. cm902
1180Ex. =
==
x=110cm. , .
x=90cm.
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) )
) (x=. t2) ( u0=0). :
21x a t u a t (I)2
= =
:
( )2(I)2 2 21 1 1K m u K m at K ma t (II)2 2 2
= = =
()
) )
) ,
. s/m15s2m30
tx
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) )
) , , .
u-t .
:
A0,9 160
x cm 72cm2
= =
:
B(20 180) 0,9
x cm 90cm2
+ = =
90cm 1s, 0,9s . .
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1
Fv
vr
1Nr
1wv
2wv
v
vr
r
2
1 v
r
1Nr
1wv
2wv
v
vTv
r
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d
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Fr
yr
Nr
wr
Tr
xr
9005
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:
1) , F = 0 W F = 0 F = mg F = 1,210-2N
2) F = (1 + 5) 10-2 1,210-2 = (1 + 5) 10-2 1,2 = 1 + 5 5 = 0,2 = 0,04m/s
3) PF = F180 = -1,210-20,04W PF = -4,810-4W
4) = 0,02m/s, : F = (1 + 5) 10-2 F = (1 + 50,02) 10-2 = 1,110-2N
F = m W F = m mg F = m = 5/6 m/s2
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1) : W = mg = 3200N
F = m W F = m = 0,1m/s2.
2) y = t2 y = 0,1202 m y = 20m
WF = Fy180 WF = 300020(-1)J WF = -60000J
P = WF/t = -3000W
3) 1 = t = 2m/s
h = h - y = 10m
: W = Ww= K mgh = m22 - m12 22 = 12 + 2gh 2 = 6m/s
4) 2 = 1 + g t t= (2 1)/g t=2,5s
t = t + t=22,5s
