A star has a mass of 1.26 x 10³⁰ kg and is moving in a circular orbit about the center of its galaxy. The radius of the orbit is 2.1 x 10⁴ light-years (1 light-year = 9.5 x 10¹⁵ m), and the angular speed of the star is 2.1 x 10^-15 rad/s. (a) Determine the tangential speed of the star. (b) What is the magnitude of the net force that acts on the star to keep it moving around the center of the galaxy?