a, Lực đẩy Át si mét

\(F_a=F_0-F'=3,9-3,4=0,5\left(N\right)\)

Thể tích của vật là

\(V=\dfrac{F_a}{d_n}=\dfrac{0,5}{10000}=5\cdot10^{-5}\left(m^3\right)\)

b, Trọng lượng riêng của vật là

\(d_v=\dfrac{F}{V}=\dfrac{3,9}{5\cdot10^{-5}}=78000\left(\dfrac{N}{m^3}\right)\)

MCD : R1//R2

a,\(R_{tđ}=\dfrac{R_1R_2}{R_1+R_2}=\dfrac{20\cdot60}{20+60}=15\left(\Omega\right)\)

b, Đổi : 10 phút =600s

\(P=\dfrac{U^2}{R_{tđ}}=\dfrac{30^2}{15}=60\left(W\right)\)

\(A=P\cdot t=60\cdot600=36000\left(J\right)\)

c,Đổi 0,5 mm²=5.10^-7 m²

\(l=\dfrac{R_2\cdot S}{\rho}=\dfrac{60\cdot5\cdot10^{-7}}{0,4\cdot10^{-6}}=75\left(m\right)\)

1. They were impressed by the (friend).....friendship ............... 

2. They enjoy the (friend).....friendly ........ atmosphere in the meeting.

3. (Beauty)beautiful ........... parks and lakes in Hanoi really attract tourists. 

4. The little girl is dancing (beauty)........beautifully ..........

5. Do you think they'll ever find a way of bringing (peace)...peach ............ to the region? 

6. They enjoyed every (peace)....peaceful .......moment in the countryside. 

7. He is old enough to live (depend)....dependent ...........

8. We are very (interest)..interested............in temples and museums in Hanoi

9. English is the (office)..........official ........ language in Singapore.

10. Like Vietnam, Malaysia has (tropic)......tropical........... climate

\(S=\dfrac{F}{p}=\dfrac{2500}{5000}=0,5\left(m^2\right)\)

Kiểm tra lại câu C

Nãy mình có làm rồi á bạn kiểm tra lại xem nha

a, \(P=d_n\cdot h=10000\cdot2,8=28000\left(Pa\right)\)

b,\(P_A=d_n\cdot h_A=10000\cdot\left(2,8-1\right)=18000\left(Pa\right)\)

c, \(P_B=d_n\cdot h_B=10000\cdot0,5=5000\left(Pa\right)\)

\(P=G\cdot\dfrac{m\cdot M}{\left(R+h\right)^2}=6,67\cdot10^{-11}\cdot\dfrac{65\cdot6\cdot10^{24}}{\left(6400\cdot1000+3\cdot1000\right)^2}=634,488\left(N\right)\)

\(F_{đh}=k\cdot\Delta l=k\cdot\left|l_0-l\right|=450\cdot\left|0,2-0,16\right|=18\left(N\right)\)