The ceiling of a long hall is 20m high. What is the max imum horizontal distance that a ball thrown with a speed of 40ms^(-1) can go without hitting the ceiling of the hall (g=10ms^(-2))?

The ceiling of a long hall is 20m high. What is the max imum horizonta

1.	The ceiling of a long hall is 20m high. What is the max imum horizontal distance that a ball thrown with a speed of 40ms^(-1) can go without hitting the ceiling of the hall (g=10ms^(-2))?
Answer» Solution :Here, H=20m, `u=40ms^(-1)`. Suppose the ball is thrown at an ANGLE `theta` with the horizontal. Now, `H=(u^(2)sin^(2)theta)/(2G)rArr=((40)^(2)sin^(2)theta)/(2XX10)` or, `sintheta=0.5 ""or, theta=30^(@)` Now `R = (u^(2).sin2theta)/(g)=((40)^(2)xxsin120^(@))/(10)` `((40)^(2)xx0.866)/(10)=138.56cm`