Luoi lam may bai nhu vay :v

a/ \(P=F_A\Leftrightarrow10.m_{vat}=10.D_{nuoc}S.\left(h-h_{noi}\right)\Rightarrow h_{noi}=h-\dfrac{m_{vat}}{D_{nuoc}.S}=0,1-\dfrac{0,16}{1000.40.10^{-4}}=...\left(m\right)\)

b/ Khoi luong khoi go sau khi khoet lo: \(m'=m-\Delta m=m-D_{vat}.\Delta S.\Delta h\left(kg\right)\)

Khoi luong chi lap vao: 

\(m''=D_{chi}.\Delta S.\Delta h\)

Khoi luong vat luc nay: \(M=m'+m''=m-D_{vat}.\Delta S.\Delta h+D_{chi}.\Delta S.\Delta h\)

\(\Rightarrow10M=10.D_{nuoc}.S.h\)

\(\Leftrightarrow m-\Delta S.\Delta h.\left(D_{chi}-D_{vat}\right)=D_{nuoc}.S.h\)

\(\Rightarrow\Delta h=\dfrac{m-D_{nuoc}.S.h}{\Delta S.\left(D_{chi}-D_{vat}\right)}=\dfrac{0,16-1000.40.10^{-4}.0,1}{4.10^{-4}.\left(11300-\dfrac{0,16}{40.10^{-4}}\right)}=...\left(m\right)\)

\(A=F.h=800.4=3200\left(J\right)\)

\(\Rightarrow t=\dfrac{A}{P}=\dfrac{3200}{1500}=...\left(s\right)\)

\(Q_{thu}=mc\left(100-30\right)=2.4200.70=...\left(J\right)\)

\(\Rightarrow Q_{can-thiet}=\dfrac{Q_{thu}}{0,8}=\dfrac{2.4200.70}{0,8}=...\left(J\right)\)

Uong nuoc co ga ma cam thay lanh :D? Dinh ly gi vay?

No la dinh luat bao toan momen dong luong, search tren wiki ra ma :v

Dong nang vat ran cung co tren mang y, chiu kho tra la ra. 

\(=\lim\limits\dfrac{n^2+an+5-n^2-1}{\sqrt{n^2+an+5}+\sqrt{n^2+1}}=\lim\limits\dfrac{an+4}{\sqrt{n^2+an+5}+\sqrt{n^2+1}}\)

\(=\lim\limits\dfrac{\dfrac{an}{n}+\dfrac{4}{n}}{\sqrt{\dfrac{n^2}{n^2}+\dfrac{an}{n^2}+\dfrac{5}{n^2}}+\sqrt{\dfrac{n^2}{n^2}+\dfrac{1}{n^2}}}=\dfrac{a}{1+1}=\dfrac{a}{2}\)

\(\lim\limits\left(u_n\right)=-1\Rightarrow\dfrac{a}{2}=-1\Rightarrow a=-2\)

Cau a co the xai L'Hospital cung ra:

L'Hospital: 

\(...=\lim\limits_{h\rightarrow0}\dfrac{6xh^2+6x^2h+2h^3}{h}=\lim\limits_{h\rightarrow0}\dfrac{6h^2+12xh+6x^2+12xh+6h^2}{1}=6x^2\)

Quang dien <=> \(\varepsilon\ge A\Leftrightarrow\dfrac{hc}{\lambda}\ge1,9\Leftrightarrow\lambda\le0,653\mu m=653nm\)

\(\Rightarrow W_d=\dfrac{6,625.10^{-34}.3.10^8}{0,35.10^{-6}}-1,9.1,6.10^{-19}=...\left(J\right)\)

\(W_d=e.U_{ham}\Rightarrow U_{ham}=\dfrac{W_d}{1,6.10^{-19}}\left(V\right)\)

\(\dfrac{hc}{\lambda}=A+W_d\Rightarrow A=\dfrac{hc}{\lambda}-W_d=\dfrac{6,62.10^{-34}.3.10^8}{0,3.10^{-6}}-2,03.1,6.10^{-19}=...\left(J\right)\)

\(\varepsilon_0=A+W_d\Leftrightarrow\dfrac{hc}{\lambda_0}=A+W_d\)

\(\Rightarrow A=\dfrac{6,62.10^{-34}.3.10^8}{0,3.10^{-6}}-2,03.1,6.10^{-19}=...\left(J\right)\)

\(\varepsilon=A+W_d'\Leftrightarrow\dfrac{hc}{\lambda}=A+W_d'\)

\(\Rightarrow W_d'=\dfrac{6,62.10^{-34}.3.10^8}{0,4.10^{-6}}-A=...\left(J\right)\)

\(W_d'=e.U_{ham}\Rightarrow U_{ham}=\dfrac{W_d'}{1,6.10^{-19}}=...\left(V\right)\)

Phần lượng tử học rõ đau đầu do phải đổi đơn vị lằng ngoằng, và số má rất nhiều :v