When a body is thrown up in a lift with a velocity `u` relative to the lift, the time of flight is found to be `t`. The acceleration with which the lift is moving up is

Options

A. `(u-"gt")/(t)`
B. `(u+"gt")/(t)`
C. `(2u-"gt")/(t)`
D. `(u)/(t)-2g`

Explanation

To solve the problem, we need to analyze the motion of a body thrown upwards in a lift that is accelerating upwards. We will use the equations of motion to derive the expression for the acceleration of the lift.

### Step-by-Step Solution:

1. **Understanding the Scenario**:
- A body is thrown upwards with an initial velocity \( u \) relative to the lift.
- The time of flight until the body returns to the same height is \( t \).
- We need to find the upward acceleration \( a \) of the lift.
...