giúp mình nha cảm ơn mọi người
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1 less crowded - more tranquil
2 faster
3 less easily
4 earlier
5 more well-furnished
Câu 1.
a) Vì hai điện tích cùng dấu nên lực tương tác của chúng là đẩy nhau.
b) Lực tương tác:
\(F=k\cdot\dfrac{\left|q_1\cdot q_2\right|}{r^2}=9\cdot10^9\cdot\dfrac{6\cdot10^{-4}\cdot4\cdot10^{-5}}{0,06^2}=60000N\)
Câu 2.
a)Lực tương tác:
\(F=k\cdot\dfrac{\left|q_1\cdot q_2\right|}{r^2}=9\cdot10^9\cdot\dfrac{q^2}{0,03^2}=4\cdot10^{-2}\)
\(\Rightarrow q_1=q_2=q=6,32\cdot10^{-8}C\)
b)Để lực tương tác là \(8\cdot10^{-2}N\) cần đặt hai điện tích:
\(F'=k\cdot\dfrac{\left|q_1q_2\right|}{r'^2}=9\cdot10^9\cdot\dfrac{4\cdot10^{-15}}{r'^2}=8\cdot10^{-2}\)
\(\Rightarrow r'\approx0,02m=2cm\)
Câu 1:
a)Lực đẩy vì điện tích giữa chúng là cùng dấu
b)\(F=\dfrac{k\left|q_1q_2\right|}{r^2}=\dfrac{9.10^9\left|6.10^{-4}.4.10^{-5}\right|}{0,06^2}=3600\left(N\right)\)
Do M là điểm chính giữa của cung AB \(\Rightarrow MA=MB\) (1)
Ta có \(\Lambda MAN=\Lambda MAB=\dfrac{1}{2}sđcungMB\) (\(\Lambda\) kí hiệu góc)
\(\Lambda MBC=\dfrac{1}{2}sđcungMB\) \(\Rightarrow\Lambda MAN=\Lambda MBC\)(2)
\(\Lambda AMN\) là góc chắn đường kính AB \(\Rightarrow\Lambda AMB=90^0\Rightarrow\Lambda AMN+\Lambda NMB=90^0\)
\(\Lambda NMC=90^0\Rightarrow\Lambda NMB+\Lambda BMC=90^0\) \(\Rightarrow\Lambda AMN=\Lambda BMC\)(3)
Từ (1) ,(2) và (3) \(\Rightarrow\Delta AMN=\Delta BMC\left(g.c.g\right)\)
3:
=3,45(123+4-27)
=3,45*100=345
2:
a: thể tích của bể là;
18*12*15=3240 lít
b: Hiện tại bể đang chứa:
3240*0,5=1620 lít
1 makes
2 doesn't eat
3 goes
4 Do-go
5 Do-agree
6 does-come
7 does-work
8 doesn't -water
9 do-do
10 Do they eat
11 am
12 rises
13 is
14 doesn't read
15 watches
Ex2
1. you don't go to school everyweekday
Do you go to school every weekday?
2. Lan doesn't play badminton with her friends today
Does Lan play badminton with her friends today?
3. Hoa doesn't like reading story books
Does Hoa like reading story books
4. Lien and Lan don't in the same class
Do Lien and Lan in the same class
5. Ba's father doesn't work in a big factory with my father
Does Ba's father work in a big factory with my father
6 She doesn't study English very well
Does she study English very well
7 They don't tall and thin
Do they tall and thin
8 His mother doesn't cook dinner for the family everyday
Does his mother cook dinner for the family everyday
9 Hoa's mother doesn't go shopping this morning
Ex3
1. Lan usually reads book recess
2 Does Ba go to the market every Sunday
3 Her father often rides his motorbike
4 Nam doesn't have short black hair
5 She usually gets up early
7 was listening - was playing
8 taught
9 playing
10 do you like - like
11 is enjoying
12 rained
13 did Lan go
14 was making
15 are running
16 saw -was having
17 will you be
18 likes
19 is sleeping
20 bought - is
21 were watching
22 will buy
23 am going to buy - am saving
24 is going to rain
25 did you live - lived
26 am having
27 were sleeping
28 is cooking
29 goes - is going
30 boils
31 did you visit