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JEE Main202125 Jul 2021Evening ShiftPhysicsMotion in One DimensionActual

A balloon was moving upwards with a uniform velocity of 10 m s - 1 . 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 )

Options

  1. A300   m
  2. B200   m
  3. C125   m
  4. D250   m

Correct answer

C. 125   m

Step-by-step solution

Object is projected as shown so as per motion under gravity, S = u t + 1 2 a t 2 - 75 = + 10 t + 1 2 ( - 10 ) t 2 ⇒ t = 5   s Object takes t = 5   s to fall on ground height of balloon from ground, H = 75 + ut = 75 + 10 × 5 = 125   m

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