A ball is dropped from a building. It takes 4s to reach the ground. The height of the building is (use g = 10 m//s^(2) )

A ball is dropped from a building. It takes 4s to reach the ground. Th

1.	A ball is dropped from a building. It takes 4s to reach the ground. The height of the building is (use g = 10 m//s^(2) )
Answer» 20 m 40 m 80 m 75 m Solution :From equation of motion. `s = UT + 1/2 at^(2)`s = h : g = a : u = o `h = 1/2"gt"^(2)` `h = 1/2 xx 10 xx (4)^(2)` , h = 80 m