За системт двох вантажів дмитро визначив прискорення віільного падіння. який результат дістав хлопчик , якщо мвантаж m2 торкнувся підлоги через 2 с після початку руху, перемістившись на відстань 2.4м？ маса першого вантажу 700 г, другого 900г.
11. Какое количество теплоты необходимо сообщить воде массой 1 кг, чтобы нагреть ее от 10° до 20° С? Удельная теплоемкость воды 4200 Дж/кг · °С?
Q=cm(t2-t1)Q=4200•1(20-10)=4200•1•10=42000Дж
ответ: в) 42000 Дж
12.Какое количество теплоты выделится в проводнике сопротивлением 1 Ом в течение 30 секунд при силе тока 4 А?
Дано: R = 1 Ом, J = 4A, t = 30 сек
По закону Джоуля-Ленца
Q = J^2•Rt = Q =( 4A)^2•1 Ом •30с = 480 Дж
ответ Г 480 Дж.
13. Работа, совершенная током за 600 секунд, составляет 15000 Дж. Чему равна мощность тока?
A=Pt
P=A/t=15000Дж/600с=25Вт
ответ б) 25 Вт
14. Два проводника сопротивлением R1 = 100 Ом и R2 = 100 Ом соединены параллельно. Чему равно их общее сопротивление?
Общее сопротивление двух равных резисторов, соединенных параллельно равно половине одного из них, то есть 50 Ом
ответ в) 50 Ом
15.Фокусное расстояние собирающей линзы равно 0,1 м. Оптическая сила этой линзы равна
D = 1/F = = 10дптр
ответ а) 10 дптр
16.Для нагревания 3 литров воды от 180 С до 1000 С в воду впускают стоградусный пар. Определите массу пара. (Удельная теплота парообразования воды 2,3 · 106 Дж/кг, удельная теплоемкость воды 4200 Дж/кг · °С, плотность воды 1000 кг/м3).
Q=Lm Отсюда масса m=Q/L, где L - удельная теплота парообразования, количество теплоты Q=cm(t2 - t1)
m=pV, где p - плотность, V - объем
m=1000 кг/м^3 * 0,003 м^3 = 3 кг
Q=4200 Дж/Кг*C * 3 кг * 82 C = 1033200 Дж Вода получила столько джоулей, и нагрелась до 100 градусов.
А необходимое для этого количество теплоты получила от пара, масса которого:
m=Q/L= 1033200 Дж/ 2300000 Дж/кг ≈ 0,45 кг
ответ г) 0,45 кг
17.Напряжение в железном проводнике длиной 100 см и сечением 1 мм^2 равно 0,3 В. Удельное сопротивление железа 0,1 Ом · мм^2/м. Вычислите силу тока в стальном проводнике.
Дано: L = 1 м - длина, S= 1 мм^2 - площадь сечения, р = 0,1 мм^2/м - удельное сопротивление, U= 0,3 в = напряжение. Найти силу тока J=?
Leonard James is a homeless man. For him, life is always hard. He is always hungry. His shoes have holes in them. He needs a haircut. His clothes are old and dirty. “What I would do with one hundred dollars!” Leonard says. This is a game he likes to play with himself to take his mind off things. He is walking down the street on a Thursday night. The winter air is cold on his face. “If I had one hundred dollars, I could buy new socks,” he says. He continues to walk down the street. “If I had one hundred dollars, I could get a haircut,” he says. He continues to walk down the street. “If I had one hundred dollars, I could buy new pants,” he says. He continues to walk down the street. “If I had one hundred dollars, I could get a hamburger,” he says. His stomach rumbles at the thought. “If I had….” Leonard looks down at the sidewalk. He cannot believe what he sees! Someone has lost his wallet. Leonard picks it up. Inside are five twenty-dollar bills. “One hundred dollars!” Leonard says. He is very excited. “Now I can buy everything I want!” Then Leonard begins to think. “But this is not my money,” he says. Leonard goes to the police station. He gives a police officer the wallet and money. “Thank you,” says the police officer. “You are a very honest man.” Leonard smiles. He turns around and begins to leave the police station. “Hold on,” the police officer says. He reaches in his own pocket and gives Leonard ten dollars. “Get yourself something to eat.”
Questions:
1) What is life like for Leonard?
A. It is hard.
B. It is easy.
C. It is warm.
D. It is full of good food.
2) How does the reader know that Leonard is poor? I. He finds a wallet. II. He has no home. III. He is always hungry.
A. I only
B. I and II
C. II and III
D. I, II, and III
3) Why does Leonard think about what he would do with a hundred dollars?
A. It helps him go to sleep.
B. It takes his mind off things.
C. The police officer asks him to.
D. He knows he will find the money.
4) What time of year is it?
A. spring
B. summer
C. fall
D. winter
5) What does Leonard say he would do with a hundred dollars? I. get a haircut II. buy new clothes III. get a hotel room
A. I only
B. I and II
C. II and III
D. I, II, and III
6) Why does Leonard's stomach rumble?
A. because he is hungry
B. because he is tired
C. because his clothes are dirty
D. because he is homeless
7) “He cannot believe what he sees.” What is another way to write this sentence?
A. He thinks what he sees is crazy.
B. He feels what he sees is good luck.
C. He thinks what he sees cannot be true.
D. He thinks what he sees is scary.
8) Why does Leonard go to the police station?
A. because he owes money
B. because he wants a reward
C. because the wallet is not his
D. because he has committed a crime
Questions (continued):
9) What kind of man does Leonard seem to be?
A. bad
B. dumb
C. good
D. old
10) As used at the end of the story, what does it mean to be honest?
A. to feel good
B. to want more
C. to be truthful
D. to be hopeful
11) How does Leonard seem to feel about what he has done?
A. angry
B. happy
C. sad
D. unsure
12) What does the police officer give Leonard?
A. advice
B. a handshake
C. money to eat
D. the one hundred dollars
13) What kind of man does the police officer seem to be?
A. angry
B. busy
C. kind
D. mean
14) Why does the police officer give Leonard ten dollars?
A. to surprise Leonard
B. so Leonard feels better about returning the wallet
C. because it is part of his job
D. because he wants to get Leonard off the streetsВітаємо в буфері обміну Gboard. Скопійований текст зберігатиметься тут.
11. Какое количество теплоты необходимо сообщить воде массой 1 кг, чтобы нагреть ее от 10° до 20° С? Удельная теплоемкость воды 4200 Дж/кг · °С?
Q=cm(t2-t1)Q=4200•1(20-10)=4200•1•10=42000Дж
ответ: в) 42000 Дж
12.Какое количество теплоты выделится в проводнике сопротивлением 1 Ом в течение 30 секунд при силе тока 4 А?
Дано: R = 1 Ом, J = 4A, t = 30 сек
По закону Джоуля-Ленца
Q = J^2•Rt = Q =( 4A)^2•1 Ом •30с = 480 Дж
ответ Г 480 Дж.
13. Работа, совершенная током за 600 секунд, составляет 15000 Дж. Чему равна мощность тока?
A=Pt
P=A/t=15000Дж/600с=25Вт
ответ б) 25 Вт
14. Два проводника сопротивлением R1 = 100 Ом и R2 = 100 Ом соединены параллельно. Чему равно их общее сопротивление?
Общее сопротивление двух равных резисторов, соединенных параллельно равно половине одного из них, то есть 50 Ом
ответ в) 50 Ом
15.Фокусное расстояние собирающей линзы равно 0,1 м. Оптическая сила этой линзы равна
D = 1/F = = 10дптр
ответ а) 10 дптр
16.Для нагревания 3 литров воды от 180 С до 1000 С в воду впускают стоградусный пар. Определите массу пара. (Удельная теплота парообразования воды 2,3 · 106 Дж/кг, удельная теплоемкость воды 4200 Дж/кг · °С, плотность воды 1000 кг/м3).
Q=Lm Отсюда масса m=Q/L, где L - удельная теплота парообразования, количество теплоты Q=cm(t2 - t1)
m=pV, где p - плотность, V - объем
m=1000 кг/м^3 * 0,003 м^3 = 3 кг
Q=4200 Дж/Кг*C * 3 кг * 82 C = 1033200 Дж Вода получила столько джоулей, и нагрелась до 100 градусов.
А необходимое для этого количество теплоты получила от пара, масса которого:
m=Q/L= 1033200 Дж/ 2300000 Дж/кг ≈ 0,45 кг
ответ г) 0,45 кг
17.Напряжение в железном проводнике длиной 100 см и сечением 1 мм^2 равно 0,3 В. Удельное сопротивление железа 0,1 Ом · мм^2/м. Вычислите силу тока в стальном проводнике.
Дано: L = 1 м - длина, S= 1 мм^2 - площадь сечения, р = 0,1 мм^2/м - удельное сопротивление, U= 0,3 в = напряжение. Найти силу тока J=?
Найдем сопротивление R = (pL)/S = 0,1 Ом
Тогда по Ому, J=U/R = 0,3/0,1 = 3А
ответ б) 3 А
7 form Reading Test
One Hundred Dollars”
Read the story. Then answer the questions below.
Leonard James is a homeless man. For him, life is always hard. He is always hungry. His shoes have holes in them. He needs a haircut. His clothes are old and dirty. “What I would do with one hundred dollars!” Leonard says. This is a game he likes to play with himself to take his mind off things. He is walking down the street on a Thursday night. The winter air is cold on his face. “If I had one hundred dollars, I could buy new socks,” he says. He continues to walk down the street. “If I had one hundred dollars, I could get a haircut,” he says. He continues to walk down the street. “If I had one hundred dollars, I could buy new pants,” he says. He continues to walk down the street. “If I had one hundred dollars, I could get a hamburger,” he says. His stomach rumbles at the thought. “If I had….” Leonard looks down at the sidewalk. He cannot believe what he sees! Someone has lost his wallet. Leonard picks it up. Inside are five twenty-dollar bills. “One hundred dollars!” Leonard says. He is very excited. “Now I can buy everything I want!” Then Leonard begins to think. “But this is not my money,” he says. Leonard goes to the police station. He gives a police officer the wallet and money. “Thank you,” says the police officer. “You are a very honest man.” Leonard smiles. He turns around and begins to leave the police station. “Hold on,” the police officer says. He reaches in his own pocket and gives Leonard ten dollars. “Get yourself something to eat.”
Questions:
1) What is life like for Leonard?
A. It is hard.
B. It is easy.
C. It is warm.
D. It is full of good food.
2) How does the reader know that Leonard is poor? I. He finds a wallet. II. He has no home. III. He is always hungry.
A. I only
B. I and II
C. II and III
D. I, II, and III
3) Why does Leonard think about what he would do with a hundred dollars?
A. It helps him go to sleep.
B. It takes his mind off things.
C. The police officer asks him to.
D. He knows he will find the money.
4) What time of year is it?
A. spring
B. summer
C. fall
D. winter
5) What does Leonard say he would do with a hundred dollars? I. get a haircut II. buy new clothes III. get a hotel room
A. I only
B. I and II
C. II and III
D. I, II, and III
6) Why does Leonard's stomach rumble?
A. because he is hungry
B. because he is tired
C. because his clothes are dirty
D. because he is homeless
7) “He cannot believe what he sees.” What is another way to write this sentence?
A. He thinks what he sees is crazy.
B. He feels what he sees is good luck.
C. He thinks what he sees cannot be true.
D. He thinks what he sees is scary.
8) Why does Leonard go to the police station?
A. because he owes money
B. because he wants a reward
C. because the wallet is not his
D. because he has committed a crime
Questions (continued):
9) What kind of man does Leonard seem to be?
A. bad
B. dumb
C. good
D. old
10) As used at the end of the story, what does it mean to be honest?
A. to feel good
B. to want more
C. to be truthful
D. to be hopeful
11) How does Leonard seem to feel about what he has done?
A. angry
B. happy
C. sad
D. unsure
12) What does the police officer give Leonard?
A. advice
B. a handshake
C. money to eat
D. the one hundred dollars
13) What kind of man does the police officer seem to be?
A. angry
B. busy
C. kind
D. mean
14) Why does the police officer give Leonard ten dollars?
A. to surprise Leonard
B. so Leonard feels better about returning the wallet
C. because it is part of his job
D. because he wants to get Leonard off the streetsВітаємо в буфері обміну Gboard. Скопійований текст зберігатиметься тут.