: Một viên đạn có khối lượng 14g bay theo phương ngang với vận tốc 400 m/s xuyên qua tấm gỗ dày 5 cm, sau khi xuyên qua gỗ, đạn có vận tốc 120 m/s. Tính lực cản trung bình của tấm gỗ tác dụng lên viên đạn?

Các câu hỏi liên quan

đây là bài làm giọng nói thụ động mong mn giúpđỡem sự giúp đỡ của mn là sự vinh hạnh ạ 1. The chief engineer was instructing all the workers of the plant. -> All the workers of the plant.... * 2. Somebody has taken some of my books away. ->Some of my books ..... * 3. They will hold the meeting before May Day. -> the meeting.... * 4. They have to repair the engine of the car. -> The engine of the car... * 5. The boys broke the window and took away some pictures. -> The window... * 6. People spend a lot money on advertising everyday.-> A lot money... * 7. They may use this room for the classroom.-> This room... * 8. The teacher is going to tell a story. -> A story.... * 9. Mary is cutting the cake with a sharp knife. -> The cake.... * 10. The children looked at the woman with a red hat. ->The woman with a red hat...... * 11. They have provided the victims with food and clothing. -> The victims .... * 12. People speak English in almost every corner of the world. -> English.... * 13. You mustn't use this machine after 5: 30 p.m. -> This machine...... * 14. You must clean the wall before you paint it. -> The wall.... * 15. They told the new pupil where to sit.-> The new pupil.... * 16. They told him of the meeting. -> He.... * 17. No one believes his story.-> His story.... * 5 points 18. A sudden increase in water pressure may break the dam.-> The dam... * 19. We must take good care of books borrowed from the library. -> Books borrowed from the library.... * 20. A man I know told me about it. ->I.... *