A balloon was moving upwards with a uniform velocity of 10 m / s. An object of finite mass is dropped from the balloon when it was at a height of 75 m from the ground level. The height of the balloon from the ground when object strikes the ground was around: (takes the value of g as 10 m / s 2 )

Question

A balloon was moving upwards with a uniform velocity of 10 m / s. An object of finite mass is dropped from the balloon when it was at a height of 75 m from the ground level. The height of the balloon from the ground when object strikes the ground was around: (takes the value of g as 10 m / s 2 ) (A) 300 m (B) 200 m (C) 125 m (D) 250 m

Tardigrade Admin · Accepted Answer

<img class="img-fluid question-image" alt="image" src="https://cdn.tardigrade.in/img/question/physics/55b3b329066b271b47ffe484bffb7f1b-.png" /> Object is projected as shown so as per motion under gravity S=u t+(1/2) a t2 -75=+10 t+(1/2)(-10) t2 ⇒ t=5 sec Object takes t=5 s to fall on ground Height of balloon from ground H=75+u t =75+10 × 5=125 m

Q. A balloon was moving upwards with a uniform velocity of 10m/s. An object of finite mass is dropped from the balloon when it was at a height of 75m from the ground level. The height of the balloon from the ground when object strikes the ground was around: (takes the value of g as 10m/s2 )

300 m

200 m

125 m

250 m

Object is projected as shown so as per motion under gravity S=ut+21​at2 −75=+10t+21​(−10)t2⇒t=5sec Object takes t=5s to fall on ground Height of balloon from ground H=75+ut =75+10×5=125m

Object is projected as shown so as per motion under gravity
$S = u t + \frac{1}{2} a t^{2}$
$- 75 = + 10 t + \frac{1}{2} (- 10) t^{2} \Rightarrow t = 5 sec$
Object takes $t = 5 s$ to fall on ground
Height of balloon from ground
$H = 75 + u t$
$= 75 + 10 \times 5 = 125 m$