Some physics students are studying periodic motion using an oscillating mass on a spring. After collecting data, they sketched the position versus time graph shown.

The function that represents the data on the graph may be written as

$x=$Acos$(t+)$ with $in[0,2)$

If the spring constant is $1\mathrm{.}19\frac{N}{m},$ then what is the mass, in kilograms?