Question

Тело массой 20 милиграм летит с высоты 5 км.Какую скорость будет имить тело возле поверхности земли.

Answer 1

Если не учитывать сопротивление воздуха, то:

Потенциальная энергия тела на высоте h:
Eп = m*g*h

Кинетическая энергия в момент падения:
Ek = m*V²/2

По закону сохранения энергии:
Ek = Eп
m*V²/2 = m*g*h
V=√ (2*g*h) =√ (2*9,8*5000) ≈ 313 м/с  - почти со скоростью звука.
(Конечно, с учетом сопротивления воздуха это тело будет иметь гораздо меньшую скорость)

(Кстати, условие m=20 мг - в этой задаче лишнее)

Answer 2

Calculation of the Velocity of an Object

To calculate the velocity of an object near the surface of the Earth, we can use the formula v = s/t, where v is the velocity, s is the distance traveled, and t is the time taken. In this case, we need to find the velocity of an object with a mass of 20 milligrams that is falling from a height of 5 km.

To calculate the velocity, we need to determine the time taken for the object to fall from the given height. We can use the equation s = vt, where s is the distance traveled, v is the velocity, and t is the time taken.

Given that the object falls from a height of 5 km, we can substitute s = 5 km and solve for t:

s = vt 5 km = v * t

To find the velocity, we need to determine the time taken for the object to fall. However, we don't have enough information to calculate the time accurately. We need to know additional details such as the initial velocity or any forces acting on the object during its fall.

Without this information, we cannot determine the velocity of the object near the surface of the Earth. If you have any additional information or specific conditions, please provide them so that we can assist you further.