An object 'O' is placed at a distance of $100 \mathrm{~cm}$ in front of a concave mirror of radius of curvature $200 \mathrm{~cm}$ as shown in the figure. The object starts moving towards the mirror at a speed $2 \mathrm{~cm} / \mathrm{s}$. The position of the image from the mirror after $10 \mathrm{~s}$ will be at _________ $\mathrm{cm}$.