Một con lắc lò xo treo thẳng đứng tại một nơi có gia tốc rơi tự do g = 10 m/s2, có độ cứng k = 50 N/m. Khi vật dao động thì lực kéo cực đại và lực nén cực đại mà lò xo tác dụng lên điểm treo lần lượt là 6 N và 2 N. Vận tốc cực đại của vật là:

Read the following andmark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 22 to 29:

 Harvard University, today recognized as part of the top echelon of the world's universities, came from very inauspicious and humble beginning.

 This oldest of American universities was founded in 1636, just sixteen years after the Pilgrims landed at Plymouth. Included in the Puritan emigrants to the Massachusetts colony during this period were more than 100 graduates of England's prestigious Oxford and Cambridge universities, and these universities graduates in the New Word were determined that their sons would have the same educational opportunities that they themselves had had. Because of this support in the colony for an institution of higher learning, the General Court of Massachusetts appropriated 400 pounds for a college in October of 1636 and early the following year decided on a parcel of land for the school; this land was in an area called Newetowne, which was later renamed Cambridge after its English cousin and is the site of the present-day university.

 When a young minister named John Harvard, who came from the neighboring town of Charlestowne, died from tuberculosis in 1638, he willed half of his estate of 1,700 pounds to the fledgling college. In spite of the fact that only half of the bequest was actually paid, the General Court named the college after the minister in appreciation for what he had done. The amount of the bequest may not have been large, particularly by today's standard, but it was more than the General Court had found it necessary to appropriate in order to open the college.

 Henry Dunster was appointed the first president of Harvard in 1640, and it should be noted that in addition to serving as president, he was also the entire faculty, with an entering freshmen class of four students. Although the staff did expand somewhat, for the first century of its existence the entire teaching staff consisted of the president and three or four tutors.

Question: The main idea of this passage is that ______________ .           

Số hạng không chứa trong khai triển là:

Question 44: Which of the following is the OPPOSITE of the word “inedible” ?         

Insect's lives are very short and they have many enemies, but they must survive long enough to breed and perpetuate their kind. The less insect-like they look, the better their chance of survival. To look "inedible" by imitating plants is a way frequently used by insects to survive. Mammals rarely imitate plants, but many fish and invertebrates do. The stick caterpillar is well named. It is hardly distinguishable from a brown or green twig. This caterpillar is quite common and can be found almost anywhere in North America. It is also called "measuring worm" or "inchworm". It walks by arching its body, then stretching out and grasping the branch with its front feet then looping its body again to bring the hind feet forward. When danger threatens, the stick caterpillar stretches its body away from the branch at an angle and remains rigid and still, like a twig, until the danger has passed.  Walking sticks, or stick insects, do not have to assume a rigid, twig-like pose to find protection; they look like inedible twigs in any position. There are many kinds of walking sticks, ranging in size from the few inches of the North American variety to some tropical species that may be over a foot long. When at rest their front legs are stretched out, heightening their camouflage. Some of the tropical species are adorned with spines or ridges, imitating the thorny bushes or trees in which they live.            

Leaves also seem to be a favorite object for insects to imitate. Many butterflies can suddenly disappear from view by folding their wings and sitting quietly among the plants that they resemble. 

Trong khai triển biết hệ số của là . Giá trị có thể nhận là:  

Question 46: Which of the following does the word “enemies” in line 1 refer to?            

Insect's lives are very short and they have many enemies, but they must survive long enough to breed and perpetuate their kind. The less insect-like they look, the better their chance of survival. To look "inedible" by imitating plants is a way frequently used by insects to survive. Mammals rarely imitate plants, but many fish and invertebrates do. The stick caterpillar is well named. It is hardly distinguishable from a brown or green twig. This caterpillar is quite common and can be found almost anywhere in North America. It is also called "measuring worm" or "inchworm". It walks by arching its body, then stretching out and grasping the branch with its front feet then looping its body again to bring the hind feet forward. When danger threatens, the stick caterpillar stretches its body away from the branch at an angle and remains rigid and still, like a twig, until the danger has passed.  Walking sticks, or stick insects, do not have to assume a rigid, twig-like pose to find protection; they look like inedible twigs in any position. There are many kinds of walking sticks, ranging in size from the few inches of the North American variety to some tropical species that may be over a foot long. When at rest their front legs are stretched out, heightening their camouflage. Some of the tropical species are adorned with spines or ridges, imitating the thorny bushes or trees in which they live.            

Leaves also seem to be a favorite object for insects to imitate. Many butterflies can suddenly disappear from view by folding their wings and sitting quietly among the plants that they resemble. 

Một lớp học có bạn học sinh trong đó có cán sự lớp. Hỏi có bao nhiêu cách cử bạn học sinh đi dự đại hội đoàn trường sao cho trong học sinh đó có ít nhất một cán sự lớp.  

Question 45: According to the passage, how does the stick caterpillar make itself look like a twig?   

Insect's lives are very short and they have many enemies, but they must survive long enough to breed and perpetuate their kind. The less insect-like they look, the better their chance of survival. To look "inedible" by imitating plants is a way frequently used by insects to survive. Mammals rarely imitate plants, but many fish and invertebrates do. The stick caterpillar is well named. It is hardly distinguishable from a brown or green twig. This caterpillar is quite common and can be found almost anywhere in North America. It is also called "measuring worm" or "inchworm". It walks by arching its body, then stretching out and grasping the branch with its front feet then looping its body again to bring the hind feet forward. When danger threatens, the stick caterpillar stretches its body away from the branch at an angle and remains rigid and still, like a twig, until the danger has passed.  Walking sticks, or stick insects, do not have to assume a rigid, twig-like pose to find protection; they look like inedible twigs in any position. There are many kinds of walking sticks, ranging in size from the few inches of the North American variety to some tropical species that may be over a foot long. When at rest their front legs are stretched out, heightening their camouflage. Some of the tropical species are adorned with spines or ridges, imitating the thorny bushes or trees in which they live.            

Leaves also seem to be a favorite object for insects to imitate. Many butterflies can suddenly disappear from view by folding their wings and sitting quietly among the plants that they resemble. 

Một nhóm có học sinh gồm nam và nữ. Hỏi có bao nhiêu cách chọn ra học sinh trong đó có cả nam và nữ.  

Question 48: Which of the following are NOT mentioned in the passage as objects that are imitated as a means of protection?       

 Insect's lives are very short and they have many enemies, but they must survive long enough to breed and perpetuate their kind. The less insect-like they look, the better their chance of survival. To look "inedible" by imitating plants is a way frequently used by insects to survive. Mammals rarely imitate plants, but many fish and invertebrates do. The stick caterpillar is well named. It is hardly distinguishable from a brown or green twig. This caterpillar is quite common and can be found almost anywhere in North America. It is also called "measuring worm" or "inchworm". It walks by arching its body, then stretching out and grasping the branch with its front feet then looping its body again to bring the hind feet forward. When danger threatens, the stick caterpillar stretches its body away from the branch at an angle and remains rigid and still, like a twig, until the danger has passed.  Walking sticks, or stick insects, do not have to assume a rigid, twig-like pose to find protection; they look like inedible twigs in any position. There are many kinds of walking sticks, ranging in size from the few inches of the North American variety to some tropical species that may be over a foot long. When at rest their front legs are stretched out, heightening their camouflage. Some of the tropical species are adorned with spines or ridges, imitating the thorny bushes or trees in which they live.            

Leaves also seem to be a favorite object for insects to imitate. Many butterflies can suddenly disappear from view by folding their wings and sitting quietly among the plants that they resemble. 

Cho là số thực dương. Số hạng không chứa trong khai triển nhị thức Niu-tơn của là: