A lift is coming from the 8th floor and is just about to reach the 4th floor. Taking the ground floor as the origin and positive direction upwards for all quantities, which one of the following is correct:
| 1. | x > 0, v < 0, a >0 | 2. | x > 0, v < 0, a < 0 |
| 3. | x < 0, v < 0, a < 0 | 4. | x > 0, v > 0, a < 0 |
(a) Hint: The motion of the lift is retarding motion.
Step 1: Find the final position of the lift.
The lift is coming in the downward direction, but it is still above the origin. So, the final position of the lift is positive.
Step 2: Find the direction of acceleration.
When the lift reaches the 4th floor, it is about to stop, hence, motion is retarding in nature hence, x > 0, a> 0.
Step 3: Find the direction of velocity.
As the lift is coming downward, the velocity will also be negative i.e., v < 0.
This can be shown on the adjacent graph.
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