có một ngôi nhà mái dốc nhà cao 12m mái cao 1,5m rộng 4m người ta bố trí 2 kim thu sét dài bằng nhau tại hai đầu hồi khoảng cách hai kim thu sét là 22m hãy tính chiều cao cảu hai cột thu sét để bảo vệ an toàn cho ngôi nhà

Identical marbles are released from the same height on each of the following four frictionless ramps . compare the speed of the marbles at the end of each ramp. explain your reasoning

Arock collection comes from which part of earth?

A5 foot by 5 foot box culvert is buried 6 feet beneath the surface of the ground. a crosssection of this very long culvert (into and out of the page) is illustrated below. assume that the soil in which the culvert is buried has the following properties: jt = 120 pcf, w = 12%, ko = 0.50, ka = 0.33, and kp = 3.00. calculate the total horizontal force per unit length of culvert (fh) felt on one of the vertical faces of the culvert.