Calculate the horizontal distance travelled by a ball throw with a velcoity ` 20 sqrt 2 ms^(-1)` without hitting the ceiling of an anditorium of heith `20 m. Use ` g= 10 ms^(-2)`.

Explanation

Here, `u=20 sqrt 2 ms^(-1) ,H=20 m,`
g=10 ms^(-2)`
As, H =(u^(2) sin theta)/ 2 g) :. 20 (20 sqrt 2)^(2) sin^(2) theta)/(2 xx 10)`
or `400 =800 sin ^(2) or sin ^(2) theta =(400)/(800) =1/2`
or `sin theta =1/(sqrt2)sin 45^(@) or theta =45^(@)`
`=((20 sqrt2)^(2) sin2 xx 45^(@) )/(10) =9800 xx1)/(10) =80 m` .