Ασκήσεις...
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Transcript of Ασκήσεις...
2015 - 2016
1
4 . 691) 4 .
4 . 69
6 . 692) 6 .
6 . 69
1 :
, ..., .
t1 = 5 s, x1 = 20 m , t2 = 10 s, x2 = 40 m, :
) = ; , : ,
) x = ; , t3 = 25 s t4 = 40 s ,
) , ( x t )
, ( t ),
.
:
)
= ....
=
)
x = .
x = .)
2 : 0 = 4 m/s , ...., .
= 2 m /s2) , t1 = 3 s, x1 = ;
1 = t1 + t1 => 1 = + ( . ) => 1 = + . => 1 = + => 1 = m) t0 t2 = 2 s,
, ;
= 2 m /s22 = t2 - t2 => 2 = - ( . ) => 2 = - . => 2 = -
=> 2 = m) , = 2 m /s2 t3 = 10 s,
x3 = ;
3 = t3 + t3 => 3 = + ( . ) => 3 = + . => 3 = +
=> 3 = m) - . ( ) )
( . 69 - 70 )
7 : : = 2 m/s2 t = 15 s = 0 m/s. = + t => = .. => = . m/s
0
. s = t + t => s = t => s = ( . ) => s = . . => => s = m 8 : : = 20 m/s t = 10 s = 0 m/s
. s = = = t = .. . => s = .. => s = . m . ,
, :
:
0 s = t + t => s = t
1 , ( t1 = 1 s ), 0
s1 = t1 + t1 => s1 = t1 => s1 = ( ) => s1 = . .=> => s1 = m 2 , ( t1 = 2 s ), 0
s2 = t2 + t2 => s2 = t2 => s2 = ( ) => s2 = . . =>=> s2 = m :
s = s2 - s1 = .. - . = m 9 : : = 20 m/s t = 30 s t = 10 s
. s = = ( + ) /2 = ( + ) /2 = /2 = => s = . m
. = s / t = . / .. = .. m/s ( . 70 - 71 )
16 : : = 9 m/s t1 = 3 s t2 = 5 s t3 = 3 s
. S = = 1 + 2 + 3
1 = = t1 = .. .. = .. => 1 = m
2 = = t2 =.. .. => 2 = .. m3 = ( 1 + 2 ) = ( 1 + 2 ) t3 = ( .. + .. ) = .. .. = .. ..
=> 3 = mS = 1 + 2 + 3 = .. + . + . => S = . m
t = t1 + t2 + t3 = .. + .. + .. = s
= S / t = .. / .. = .. m/s
. 3s : = / t = ( ) / ( t t ) = ( .. .. ) / ( .. .. ) = / = . m/s2 3s :
= / t = ( ) / ( t t ) = ( .. .. ) / ( .. .. ) = / = . m/s2 19 : : o = 10 m/s t1 = 5 s t2 = 10 s t3 = 5 s t4 = 5 s . S = = 1 + 2 + 3 + 4
1 = ( 1 + 2 ) = 2 = =
3 = =
4 = = S = t =
= S / t = .. / .. = .. m/s
. 5s : = / t = ( ) / ( t t ) = ( .. .. ) / ( .. .. ) = / = . m/s2 . S = = 1 + 2 + 3 + 41 = = t1 = .. .. = .. => 1 = m
2 = = t2 =.. .. => 2 = .. m3 = ( 1 + 2 ) = ( 1 + 2 ) t3 = ( .. .. ) = .. .. = .. ..
=> 3 = m3 = ( 3 + 3 ) = ( 3 + 4 ) t3 = ( .. .. ) = .. .. = .. ..
=> 3 = mS = 1 + 2 + 3 + 4 = .. + . + . + . => S = . m t = t1 + t2 + t3 + t4 = .. + .. + .. = s = S / t = .. / .. = .. m/s ( . 70 - 71 )
10 : : = 8 +2t m/s t1 = 2 s t2 = 4 s
. = 8 + 2t = 0 + t, 0 = 8 m/s = 2 m/s2 . :
s = t + t
2 , ( t1 = 2 s ), s1 = t1 + t1 => s1 = .. .. + .. ( .. ) => s1 = .. + .. .. =>
s1 = .. + .. => s1 = m ( 1 )
4 , ( t2 = 4 s ), s2 = t2 + t2 => s2 = .. .. + .. ( .. ) => s2 = .. + .. .. =>
s2 = .. + .. => s2 = m ( 2 )
:
s = s2 - s1 = .. - . = m
12 : : d = 200 m t = 10 s = 30 m/s
d t1 t2t = t2 - t1 = t . :
= + t => = + t => .. = + .. ( 1 )
s = t + t => d = t + t => .. = .. + ( ... ) =>
.. = .. + ... => .. = .. + ... ( 2 )
11 : : t = 10 s 1 = 50 m/s 2 = 30 m/s
B. ( )
= ( t ) . t =.. s = .. m/s. B.
s1 10 , ( t = 10 s ).
1 1, :1 = 1 => 1 = t 1 => 1 = .. .. => 1 = .. => 1 = m
s2 10 , ( t = 10 s ).
2 2, :
2 = 2 => 2 = t 2 => 2 = .. .. => 2 = m s :
s = s2 - s1 = 1 - 2 = .. - . = m . ,
1 = 2, t.
1 = ( + ) 11 = 2 = 2
1 2 10 t
1 = 2 => ( + ) 1= 2
1 = ( + ) 1 => 1 = [( t + ( t 10 )] 1 => 1 = [( .. + ( .. 10 )]
=> 1 = ( .. 10 ) (1) => 1 = t + (1)
2 = 2 => 2 = .. t => 2 = .. t (2)1 = 2 => ( + ) 1= 2 => (1) = (2) => t + = .. t => => .. t = . => t = 17 : : 0 = 10 m/s = 2 m/s2
. : = / 2 :
= - t => / 2 = - t => .. / 2 = .. - .. t => .. / 2 = .. - .. t
=> .. = .. - .. t => .. - .. = .. t => .. = .. t => t = .. s
2,5 , ( t = 2,5 s ) :s = t - t => s = . . - . ( . ) => s = .. - . . => s = .. - . . => s = .. m
B. = - t = 0 m / s : = - t => 0 = - t => = t => / = t => .. / .. = t => t = .. s
13 : : 0 = 72 Km/h => 0 = 20 m/s = 10 m/s2 t1 = 0,7 s d = 50 m
s = t => s1 = => s1 = .. m
s = d - s1 => s = .. - .. => s = .. m ( )
: : = - t
: 0 = - t :
= - t => 0 = - t => = t => t = / ( 1 )
: s = t - t ( 1 ) :
s = t - t => s = ( / ) - ( / ) => s = 2 / - / => s = 2 / - / => s = 2 /
:
s = 2 / => s = (.. )2 / => s = m ( ) () () . 2
1.2.1 :
1) ;
2) ;
)
)
3) ;
)
)
)
1.2.2 : 4) ;
5) ;
6) ; :
7) ; : : = 20 cm F = 80 N
A. Hooke : F = K x
: 80 = . 20 = . / . = 4 / cm :
( cm )
( N )
.
()
( cm )
. . :
= . = .. / .. = .. / cm,
. 1 : : F = 80N F = 60N
. 0 : F = F1 + F2 => F = .. +.. => F =
:
B. 180 : F = F1 - F2 => F = .. - .. => F =
:
2 :
. F = F1 + F2 - F3 => F = .. +.. -. => F =
:
. F = F1 - F2 - F3 => F = .. - .. - . => F =
:
. F = F1 + F2 + F3 => F = .. +.. + . => F =
:
3 : : F = 10N . F1 = 4 F2 => F = 4 F2 + F2 => F = 5 F2 => F / 5 = F2 => . / 5 = F2 => F2 = F1 =4 F2 => F1 = 4 . => F1 =
:
. F1 =3 F2 => F = 3 F2 - F2 => F = 2 F2 => F / 2 = F2 => / 2 = F2 => F2 =
F1 =3 F2 => F1 = 3 . => F1 =
:
5 : : F = 22 N F = 7 N
F1 - F2 - F3 = 0 => F3 = F1 - F2 = .. - => F3 = . N
:
6 : :