The cone falling with a speed $v_0=2\mathrm{.}7\frac{m}{s}$ strikes and penetrates the block of packing material. The acceleration of the cone after impact is $d=g-c{y}^2$ where $g$ is the acceleration of gravity, $c$ is a positive constant and $y$ is the penetration distance. If the maximum penetration depth is observed to be $y_m=0\mathrm{.}06m$ determine the constant $c$ in $\frac{1}{m}{s}^2$