Question

stone dropped ina well hits water surface after 2 sec.wat is the depth of well and wid wat speed will the stone hit water surface

Answer 1

Assuming no initial velocity,

Distance Travelled (s)=0.5*g*t^2,

g is accelaration

t is time taken

S = 0.5 * 9.81 * 2 * 2

S= 19.62 m

This is assuming that there is no drag effect or any other effect that would alter the course or speed of the object. But in real world, an object can’t accelerate past it’s terminal velocity, due to drag force. But within 2 seconds, it won’t make much difference.

NOW, to the interesting part, the depth of the well cannot be known from this. We can know the depth at which the water surface is in relation to the point from where the stone is dropped.

For all we know, the depth could be 400 m or just 40 m. And the stone could have been dropped from ground level, below ground level or above ground level.

All we know, is the stone that is dropped, traveled 19.62 m before hitting the surface of the water.