Chất điểm 1 có khối lượng $m_1=50$ g dao động điều hoà quanh vị trí cân bằng của nó với phương trình dao động $x_1=5\cos\left(\pi t+\dfrac{\pi}{6}\right)$ cm. Chất điểm 2 có khối lượng $m_2=100$ g dao động điều hoà quanh vị trí cân bằng của nó với phương trình dao động $x_2=5\cos\left(\pi t-\dfrac{\pi}{6}\right)$ cm. Tỉ số cơ năng trong quá trình dao động điều hoà của chất điểm 1 so với chất điểm 2 bằng

PHẦN II. Câu trắc nghiệm đúng sai. Thí sinh trả lời từ câu 1 đến câu 2. Trong mỗi ý a), b), c), d) ở mỗi câu, thí sinh chọn đúng hoặc sai

Read the following advertisement and mark the letter A, B, C, or D   to indicate the option that best fits each of the numbered blanks from 1 to 6.

JOIN THE INTERNATIONAL CULTURAL FESTIVAL!

    Are you looking (1) ______ a fun and exciting event? Come to the International Cultural Festival this weekend! This amazing event brings together cultures from around the world, offering you the chance to enjoy (2) ______ different traditions, foods, and music. This is a great chance to make new friends and (3) ______ traditions from various countries. A special part of the festival is the art exhibition, where (4) ______ works from local and international artists will be displayed. Don’t miss the opportunity to experience (5) ______ variety of cultural activities all in one place. Everyone is welcome to join the celebration, and there’s something for all ages to enjoy. The festival (6) ______ at the city park from 10 AM to 5 PM on Saturday. See you there!

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 23 to 30.

     Animals are primed to be wary through natural selection rather than scary television shows, but like humans, they often make mistakes when watching out for threats.

     Identifying stealthy predators is already a difficult task. From the perspective of a songbird, a harmless crow flying overhead may look similar to a raptor. But predator identification is made more challenging by the fact that prey animals often juggle multiple activities like foraging, keeping an eye on competitors and courting mates, all at the same time.

     This can be made easier by working as a group. Members of a school of fish, flock of birds or herd of antelope can share the task of watching out for predators. When an animal detects a predator, they share this information with other group members directly, by producing a warning, or inadvertently, by preparing to flee. The group as a whole can then respond by fleeing, hiding or adopting a defensive position.

     But this information is not always reliable. When predators are harder to identify, perhaps because they are well camouflaged, an animal may be more likely to mistake unrelated sounds or movements for a predator. Research found that bumblebees were more likely to produce false alarms having previously been exposed to highly camouflaged goldenrod crab spiders than bees that were unaccustomed to them.

     Some species are instead simply more vulnerable to predators than others. This can be because they are not fast enough to escape a close encounter or not equipped to fight a predator off. For these species, ignoring a true alarm is more likely to result in death, so it may be beneficial to follow a “better-safe-than-sorry” principle and pay the cost of being occasionally wrong. Willow tits produce alarm calls in response to most large aerial objects including planes and crows. This is because they are typically hunted in ambush attacks in which they are unlikely to escape. So the costs of alarm calling at a few planes becomes dwarfed by the threat of being killed in an attack.

(Adapted from https://www.thesouthafrican.com/animals/why-prey-animals-often-see-threats)

Quỹ đạo của chuyển động ném ngang là một

Một viên đạn bằng bạc có khối lượng 2,00 g bay với tốc độ \(2,00 \cdot {10^2}\;{\rm{m}}/{\rm{s}}\) đến xuyên vào một bức tường gỗ. Nhiệt dung riêng của bạc là \(0,234\;{\rm{kJ}}/({\rm{kg}}.{\rm{K}}).\) Coi viên đạn không trao đổi nhiệt với bên ngoài và toàn bộ công cản của bức tường chi dùng để làm nóng viên đạn, nhiệt độ của viên đạn sẽ tăng thêm bao nhiêu kelvin (viết kết quả đến một chữ số sau dấu phẩy thập phân)?