oper написал(а):Risto_Koivula,_Tampere написал(а):
c/m = 2.6g/vo² =26ms⁻²/(250ms⁻¹)² = (2403m)⁻¹ = -k
В в каком классе учитесь?
c/m имеет размерность kg⁻¹, а 2.6g/vo² имеет размерность m⁻¹.
Как вы из килограмм получили метры? Нельзя c/m приравнивать 2.6g/vo². Вам по физике двойка.
https://en.wikipedia.org/wiki/Drag_(physics)
You do not know mathematics.
According to Newton´s second law and his drag law, for a body moving in a dragging fluid
v´(t)/v²(t) = constant = c/m, when no extra forces influence. c =ρAC/2. The dimension c is that of ρA = kg/m³xm² = kg/m. The mass dimension comes here from the mass of the gas or fluid.
When we know a constant in one point of a trajectory, we know it in every point.
In this case we know at the disconnection point t = 0 both tehe speed V80) = 250 m/s and the acceleration v´(0) = -2g (or 2.6g, difference is less than one km in falling distance.
A verification:
v´(t)/v²(t) = - c/m = constant = -2g/vo² = -20ms⁻²/(250ms⁻¹)² = - (3125m)⁻¹ = -k
Integrating implicitely:
-v⁻¹(t) = -k(t - to), where to is integation constant, which gives
v(t) = k⁻¹(t - to)⁻¹
v(0) = 250ms⁻¹ = vo = -k⁻¹to⁻¹, which gives
to = -k⁻¹vo⁻¹ = - vo/(2g) = - 250ms⁻¹/(20ms⁻²)⁻¹ = - 12.5s.
Now:
v´(t) = - k⁻¹ (t - to)⁻²
v´(0) = - k⁻¹to⁻² = - k vo² = - vo² 2g/vo² = -2g.
Отредактировано Risto_Koivula,_Tampere (2022-01-06 00:55:25)