A thin string $2\mathrm{.}50$ m in length is stretched with a tension of $90\mathrm{.}0$ N between two supports. When the string vibrates in its first overtone, a point at an antinode of the standing wave on the string has an amplitude of $3\mathrm{.}50$ cm and a maximum transverse speed of $28\mathrm{.}0$ m$>$s$.($a$)$What is the string$$s mass? $($b$)$ What is the magnitude of the maximum transverse acceleration of this point on the string?