Question

[Nguyễn Thái Sơn]

1) 1 vat duoc nem thang dung len cao tu do cao h voi van toc dau 72km/h  bo qua ma sat g = 10m/s². Khi cham dat van toc cua vat 30m/s 

a) Tim do cao h

b) Tim do cao cuc dai

c)  Tim van toc tai noi co W_{dong nang} = 5W_{the nang}