$.(1$ pt$)$ Consider Procedure D$.$ Suppose your spring has a mass of $11\mathrm{.}4$ g$,$ your weight holder has a mass of $2\mathrm{.}8$ g$,$ and you place a $15\mathrm{.}0-$g mass on the weight holder. What is the value for the effective mass that you would use in Procedure D$?($show your work$)$

$3.(2$ pts$)$ Suppose you pull down on the mass from Question $2,$ set the system into oscillation and find that the system has a period of oscillation equal to $0\mathrm{.}94$ s$.$ Calculate the spring constant using the effective mass from Question $2$ and the period of oscillation. $($Show your work$)$