Question

A lift is coming from 8^th floor and is just about to reach 4^th floor. Taking ground floor as origin and positive direction upwards for all quantities, which one of the following is correct?

• A. $x < 0, ⥂ ⥂ v < 0, ⥂ ⥂ a > 0$
• B. $x > 0,v < 0,a < 0$
• C. $x > 0,v < 0,a > 0$
• D. $x > 0,v > 0,a < 0$

Answer 1

Answer: (A)

$x < 0, ⥂ ⥂ v < 0, ⥂ ⥂ a > 0$

Answer 2

As lift is coming from 8^th to 4^th floor, it is retarding, i.e., a is acting upwards, so a > 0 and the value of x becomes less hence negative, i.e., x < 0, velocity is downwards (i.e., negative) so, v < 0.