28. A train is blowing its whistle while traveling at a speed of 33.0 m/s. The speed of sound is 343 m/s. Observer A isp^rectlvjn'ft^ntjof the train, while observer B is directly behind it Find the whistle frequency hearcf i\v A~arid that heard by B. (5 pts) M20rk= F oQszwtit, a \s oe&cmft G> 1-