A) Show that the surface temperature of a star can be inferred from measurements of blackbodyfluxes at two different frequencies, even if the stellar radius and distance are unknown. b) Explain why in practice this method does not work well if both frequencies are on theRayleigh-Jeans side of the spectrum, hνkT.
c) Derive a simple, approximate expression for the temperature when both measurements areon the Wien tail, hνkT.
d) Derive an expression for the star’s radius if a distance measurement is also available (e. g.,from parallax).

Review multiple-concept example 7 in this chapter as an aid in solving this problem. in a fast-pitch softball game the pitcher is impressive to watch, as she delivers a pitch by rapidly whirling her arm around so that the ball in her hand moves in a circle. in one instance, the radius of the circle is 0.626 m. at one point on this circle, the ball has an angular acceleration of 66.1 rad/s2 and an angular speed of 12.6 rad/s. (a) find the magnitude of the total acceleration (centripetal plus tangential) of the ball. (b) determine the angle of the total acceleration relative to the radial direction.