A-balloon-ascends-vertically-with-a-constant-speed-for-5-seconds-when-a-pebble-falls-from-it-reaching-the-ground-in-5-s-The-speed-of-the-balloon-is-

Question Number 15116 by Tinkutara last updated on 07/Jun/17

A balloon ascends vertically with a

constant speed for 5 seconds, when a

pebble falls from it reaching the ground

in 5 s . The speed of the balloon is ?

Answered by ajfour last updated on 07/Jun/17

{p e b b l e}^{'} s i n i t i a l v e l o c i t y = v e l o c i t y

o f b a l l o o n = u

s = u t + \frac{1}{2} {a t}^{2}

d i s p l a c e m e n t o f p e b b l e b y t h e

t i m e i t r e a c h e s g r o u n d = h e i g h t

t h r o u g b w h i c h b a l l o o n a s c e n d s

i n 5 s e c o n d s .

- {u t}_{0} = u t - \frac{1}{2} {g t}^{2}

t_{0} = 5 s a n d t = 5 s, s o

- 5 u = 5 u - \frac{1}{2} (10) (25)

\Rightarrow 10 u = 125

u = 12.5 m / s .

Commented by Tinkutara last updated on 07/Jun/17

Thanks Sir!

Answered by mrW1 last updated on 07/Jun/17

v 5 = - v 5 + \frac{1}{2} \times 10 \times 5^{2}

v = 12.5 m / s

Commented by Tinkutara last updated on 07/Jun/17

Thanks Sir!