1.

A balloon is ascending at the rate of `9.8 m//s` and is 39.2 m above the ground when a package is dropped. (a) How long does the package take to reach the ground? (b) with what speed does it hit the ground ? `(g = 9.8 m//s^(2))`

Answer» Correct Answer - (a) 4 s (b) 29.4 m/s
Taking downward direction `+ve , u = - 9.8 m//s, s = 39.2 m " and " a = g = +9.8 m//s^(2)`
(a) `39.2 = - 9.8 t + (1)/(2) (9.8) t^(2)`
`4.9 t^(2) - 9.8 t - 39.2 = 0`
`t^(2) - 2t - 8 = 0`
`(t - 4) (t + 2) = 0`
`t = 4s`
(b) `v = u + g t = - 9.8 xx 4 = 29.4 m//s`


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