A stone drop from the edge of the roof of a multistoried building. Calculate the teme taken by the pot cross to a particular distance AB of height 2.9m, the upper point A being 19.6m below the roof.

To calculate the time taken by the stone to fall to a particular distance AB, we can use the equations of motion.

The basic equation we will use is the equation for downward motion under gravity, given by:

s = ut + (1/2)gt^2

Where:
- s is the vertical distance traveled (in this case, 2.9m)
- u is the initial vertical velocity (which is 0 since the stone is dropped)
- g is the acceleration due to gravity (approximately 9.8 m/s^2)
- t is the time taken to travel the distance AB (which we need to calculate)

We need to rearrange this equation to solve for t. Rearranging, we get:

2.9 = 0 + (1/2)(9.8)t^2
2.9 = 4.9t^2
t^2 = 2.9 / 4.9
t^2 ≈ 0.5918
t ≈ √0.5918
t ≈ 0.768 seconds

So, the time taken by the stone to fall to a height of 2.9m (distance AB) is approximately 0.768 seconds.