Lift A is going up with velocity 20m/s and acceleration of $8 m / s^{2}$ in the downward direction. While lift B is going down with 10m/s and acceleration of $+ 2 m / s^{2}$ in upward direction. At this moment a bolt in the ceiling of lift A gets loose and falls. Height of the lift is 16 m.Find the displacement of bolt relative to B when it hits the floor of A.

20 m

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24 m

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32 m

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36 m

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Solution

The correct option is B
24 m

Displacement of bolt at 4s:
$S_{b} = 20 \times 4 - \frac{1}{2} 10 (4)^{2} = 0 m$

Displacement of lift B at 4s:
$S_{B} = 10 \times 4 - \frac{1}{4} 10 (4)^{2} = 24 m d o w n w a r d$

So displacement of bolt relative to B:
$\frac{S_{b}}{b} = 0 - 24 = - 24 m$

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Similar questions

Q. Lift A is going up with velocity 20m/s and acceleration as

8 m / s^{2}

in the downward direction. While lift B is going down with 10m/s and acceleration of

+ 2 m / s^{2}

in upward direction. At this moment a bolt in the ceiling of lift A gets loose and falls. Height of the lift is 16 m.

What is the velocity of bolt relative to lift B when it hits the floor of A.?

Lift A is going up with velocity 20 m/s and acceleration as $8 m / s^{2}$ in the downward direction. While lift B is going down with 10 m/s and acceleration of $+ 2 m / s^{2}$ in upward direction. At this moment a bolt in the ceiling of lift A gets loose and falls. Height of the lift is 16 m.

What is the velocity of bolt relative to lift B when it hits the floor of A.?

Lift A is going up with velocity 20 m/s and acceleration a equal to $8 m / s^{2}$ in the downward direction. While lift B is going down with 10 m/s and acceleration of +2 $m / s^{2}$ in upward direction. At this moment a bolt in the ceiling of lift A gets loose and falls. Height of the lift is 16 m. Find the time taken by bolt to hit the floor of A.

Q. An open lift is moving upwards with velocity

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. It has an upward acceleration of

2

m / s^{2} .

A ball is projected upwards with velocity

20 m / s

relative to ground. Find displacement of lift and ball at that instant.

Q. A loose bolt falls from the roof of a lift of height

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The correct option is B 24 m Displacement of bolt at 4s: Sb=20×4−1210(4)2=0m Displacement of lift B at 4s: SB=10×4−1410(4)2=24m downward So displacement of bolt relative to B: Sbb=0−24=−24m

The correct option is B
24 m

Displacement of bolt at 4s:
$S_{b} = 20 \times 4 - \frac{1}{2} 10 (4)^{2} = 0 m$

Displacement of lift B at 4s:
$S_{B} = 10 \times 4 - \frac{1}{4} 10 (4)^{2} = 24 m d o w n w a r d$

So displacement of bolt relative to B:
$\frac{S_{b}}{b} = 0 - 24 = - 24 m$