.
Δ t
(1)
- Ds , D t.
( ) ,
(2)
- . (.2). /.
. , , , , . u, u . u = u + u, - u = u - u.
υ ,υ,υ z (. 2):
.2.
, :
(3)
(υ = const). v, .
- ,
(4)
Δυ - Δ t.
v :
(5)
, ,
= τ + n. (6)
( ) τ ,
. (7)
(. 3)..
() n ,
(8)
R - .
, ; (.3).
. (9)
(.3)
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. , , - .
ם = 0 = τ. ם= 0 τ = 0, ; ם= 0 τ = const .
:
d s = ud t → s = ∫ud t = u∫d t = u t + s 0, (10)
s 0 - t = 0. .
υ (t) s (t) .4.
u = ∫ d t = ∫ d t,
u= t + u0, (11)
u0 - t =0.
s = ∫ud t = ∫(t + u0)d t. ,
s = t 2/2 + u0 t + s 0, (12)
s 0 - ( t = 0). (11), (12) .
(t), υ (t) s (t) .5.
g = 9,81 /2 : g 0, g 0. (11):
u= u0 + g t;(13)
h = gt 2/2 + u0 t + h 0. (14)
, (, , ,). : (.6). ; - : . . u0 - , α ( ). :
u0x = ux = u0 cos α = const; (15)
u0 = u0 sinα. (16)
. 6.
(13)
u = u0 - g t = u0 sinα. - g t;
u = u0 = u0 cos α = const.
, , u = 0. :
u = u0 - g t = u0 sinα. - g t = 0 → t = u0 sinα/ g. (17)
, (14):
h max= u0 t - gt 2/2=u0 sinα u0 sinα/ g g (u0 sinα/ g)2/2 = (u0 sinα)2/(2 g) (18)
,
t 1 =2 t = 2u0 sinα / g. (19)
(15) (19) :
= u t 1 = u0 cosα 2u0 sinα/ g = 2u02cosα sinα/ g. (20)
g; , .3.
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