An elevator without a ceiling is ascending up with an acceleration of $5{ \mathrm{ms}}^{-2}$ A boy on the elevator shoots a ball in vertical upward direction from a height of $2 m$ above the floor of elevator. At this instant the elevator is moving up with a velocity of $10{ \mathrm{ms}}^{-1}$ and floor of the elevator is at a height of $50 \mathrm{m}$from the ground. The initial speed of the ball is $15{ \mathrm{ms}}^{-1}$ with respect to the elevator. Consider the duration for which the ball strikes the floor of elevator in answering following questions. $\left(g=10m{s}^{-2}\right)$

The time in which the ball strikes the floor of elevator is given by

• A

  $2.13 \mathrm{s}$

• B

  $2.0 \mathrm{s}$

• C

  $1.0 \mathrm{s}$

• D

  $3.12 \mathrm{s}$

The maximum height reached by ball, as measured from the ground would be

• A

  $73.65 \mathrm{m}$

• B

  $116.25 \mathrm{m}$

• C

  $82.56 \mathrm{m}$

• D

  $63.25 \mathrm{m}$

Displacement of ball with respect to ground during its flight would be

• A

  $16.25 \mathrm{m}$

• B

  $8.76 \mathrm{m}$

• C

  $20.24 \mathrm{m}$

• D

  $30.56 \mathrm{m}$

The maximum separation between the floor of elevator and the ball during its flight would be

• A

  $12 \mathrm{m}$

• B

  $9.5 \mathrm{m}$

• C

  $15 \mathrm{m}$

• D

  $7.5 \mathrm{m}$

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