Скільки часу потрібно для того, щоб унаслідок нікелювання виробу на його по­ верхні утворився шар двовалентного нікелю завтовшки 0,03 мм? Скільки енергії (у Вт- год) буде затрачено? Площа поверхні виробу дорівнює 120 см2. Напруга на клемах ванни — 1,8 В, опір розчину — 3,75 Ом. Заранее

1.mozhete not rewrite the essay. 2.mozhete stay: in fact you have the time. 3. you can stay if you want. 4. you do not have to stay if you do not want. 5. you do not have to talk to him about it. 6. can you tell him about it. we can not repeat these rules: we know them. 7. it must be home now. 8. they maybe came to us yesterday, but we were not at home. 9. it can not be that he did not know this picture. 10. you do not have to go there: they are very bad people. 11.tebe should go there: they are waiting for you. 12. can i look at your picture? 13. it can not be that he was for so many years: he looks very young. 14. if my sister will not buy me a coffee, i have to go to the store itself. 15. i can not find my watch. i could not leave them at work. 16. i had a lot of books when i was preparing the report. 17. you can not immediately agree: think a few days. 18. can you show me your picture?

Удлинение кольца равно первоначальной длине кольца L₀ = 2*π*R₀
Сила упругости возникшая в кольце равна центростремительной силе
F = k*L₀ = m*v²/R, R = 2*R₀ - радиус вращающегося кольца
k*2*π*R₀ = m*ω²*R²/R = m*ω²*(2*R₀)²/(2*R₀) = 2*m*ω²*R₀
π*k =m*ω² => ω² = π*k/m
ω = √(πk/m)
Нашел, как добавить
σ = E*(L-L₀)/L₀ = E*ΔL/L₀ => ΔL = σ*L₀/E
σ - предел прочности резины
Е - модуль Юнга резины
Удлинение кольца ΔL = σ*2*π*R₀/E
k*ΔL = mv²/R
R = (L₀ + ΔL)/(2*π) = (2*π*R₀ + 2*π*R₀*σ/E)/(2*π) = R₀ + R₀*σ/E = R₀*(1 + σ/E)
k*σ*2*π*R₀/E = m*ω²*R
2*π*k*R₀*σ/E = m*ω²*R₀*(1 + σ/E)
2*π*k*σ/E = m*ω²*(1 + σ/E)
ω² = 2*π*k*σ/(E*m*(1 + σ/E))
ω = √(2*π*k*σ/(E*m*(1 + σ/E)))
ω = √(2*π*k*σ/(m*(E + σ)) - угловая скорость при которой произойдет разрыв шнура