Trong 1 bình có chứa m1=1kg nước ở t°1=10℃, người ta thả vào bình 1 cục đá m2 = 5kg ở t°2= -20℃. c nước = 4200 j/kg.k, c đá = 1800 j/kg.k, λ= 34 x 10^4.Tính t° của hệ khi có cân bằng nhiệt và lượng nước có trong hệ.

Dear Penpal,

I am so excited to hear that you will be coming to Vietnam this summer and that we will be classmates! I am sure you will have a great time here and make many new friends.

To help you survive at school, here are some tips that I think will be useful:

   1. Be respectful: Respect is very important in Vietnamese culture, so make sure to show respect to your teachers and classmates. This includes using proper titles when addressing them and being polite in your interactions.

   2. Be punctual: Being on time is also important, so make sure to arrive at school on time and be ready for class.

   3. Dress appropriately: Make sure to follow the school’s dress code and wear appropriate clothing. This usually means wearing the school uniform or dressing modestly.

   4. Participate in class: Don’t be afraid to participate in class and ask questions if you don’t understand something. Your teachers and classmates will appreciate your engagement and willingness to learn.

Make friends: Making friends is a great way to feel more comfortable at school and have a support system. Don’t be afraid to introduce yourself to your classmates and join in on group activities.

I hope these tips help you have a successful and enjoyable time at school in Vietnam. I can’t wait to meet you in person!

Best, [Your Name]