Предмет: Физика, автор: Ekaterinka0

Человек прыгнул вверх. В результате взаимодействия с Землёй импульс человека изменился. По закону сохранения импульса ровно на столь ко же по модулю изменился импульс Земли. Равно ли при этом изменение кинетической энергии человека изменению кинетической энергии Земли? Докажите своё утверждение.

Ответы

Автор ответа: ЮрВас
0
По зак сохр имп
0+0=mv-Mu
mv=Vu
u=mv/M
Кин эн человека E1=mv²/2
Кин эн Земли E2=Mu²/2=Mm²v²/(2M²)=m²v²/(2M)=[mv²/2]•m/M=E1•m/M≈E1•0=0.
Изм кин эн Земли ничтожно малО.
Автор ответа: kmike21
0
масса человека m₁, масса Земли m₂,
измнение скорости человека Δv₁, Земли Δv₂
измнение импульса человека Δp₁, Земли Δp₂
Δp₁=Δp₂
m₁Δv₁=m₂Δv₂
Δv₁=m₂Δv₂/m₁
ΔEк₁=m₁Δv₁²/2=m₁(m₂Δv₂/m₁)²/2=m₁m₂²Δv₂²/2m₁²=m₂²Δv₂²/2m₁= (m₂/m₁)m₂Δv₂²/2=(m₂/m₁)ΔEк₂
так как m₂≠m₁, то ΔEк₁≠ ΔEк₂



















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