Answer:
The height is 3.1m
Explanation:
Here we have a conservation of energy problem, we have a conversion form eslastic potencial  energy to gravitational potencial energy, so:
[tex]E_e=\frac{1}{2}K*x^2\\E_e=\frac{1}{2}18N/m*(9.5*10^{-2}m)^2\\E_e=0.081J[/tex]
then we have only gravitational potencial energy when the ball is at its maximun height.
[tex]E_g=m*g*h[/tex]
because all the energy was transformed Eg=Ee
[tex]h=\frac{0.081J}{9.8m/s^2*m}[/tex]
searching the web, the mass of a ping pong ball is 2.7 gr in average. so:
[tex]h=\frac{0.081J}{9.8m/s^2*(2.7*10^{-3}kg)}\\h=3.1m[/tex]
