CBSE Class 12-science Answered
Here let us take 'x' be the distance covered by the girl in time t.
If 'y' is length of shadow in time 't' min then the rate at which the
Length of shadow is increasing is which is required.
From the figure it is clear that
Now differentiating the above equation with respect to it, we get
But it is given,
This means that the shadow is increasing at the rate of 12m/min.