Part A

Two soccer players, Mia and Alice, are running as Alice passes the ball to Mia. Mia is running due north with a speed of $6\mathrm{.}50\frac{m}{s}.$ The velocity of the ball relative to Mia is $4\mathrm{.}00\frac{m}{s}$ in a direction $30\mathrm{.}0$ east of south.

What is the magnitude of the velocity of the ball relative to the ground?

Express your answer with the appropriate units.

$v=$