Question

A lift is coming from 8th floor and is just about to reach 4th 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

Given: A lift is coming from 8th floor and is just about to reach 4th floor.

To find: Taking ground floor as origin and positive direction upwards for all quantities, which one of the following is correct?

Solution:

• Now we have given that the lift is coming in downwards direction.

• Since its direction is downwards so displacement will be negative.

• When the lift is near to 4th floor it is about to stop.

• So the motion is retarding in nature.

                  x < 0 and  a > 0  

• Now, since displacement is negative direction, so velocity will also be negative.

                  v < 0

Answer:

          So the first option (a) x < 0, v < 0, a > 0  is correct.