An aeroplane moving horizontally with a speed of `720 km//h` drops a food pocket, while flying at a height of 396.9 m . the time taken by a food pocket to reach the ground and its horizontal range is (Take `g = 9.8 m//sec`)

Options

A. `9 s, 1800 m`
B. `8 s, 1500m`
C. `3 s, 2000m`
D. `5 s, 500 m`

Answer

A

Explanation

(a): Velocity of airplane`v=720 km//h`
`v=200m//s`
`v=200m//s`

Time taken by food packet from height H is t .
`S_(y)=v_(y)t+(1)/(2)"gt"^(2)`
`H=(1)/(2)"gt"^(2)`
`=sqrt((2H)/(g))=sqrt((2xx396.9)/(9.8))=9s`
Horizontal range `R=vxxt`
`=200xxsqrt((2H)/(g))`
`=200xx9`
`=1800m`