A wireless transmitting microphone is mounted on platform that can roll down an incline, directly away from a loud speaker that is mounted at the top of the incline. The loud speaker broadcasts a tone that has a fixed frequency of 1.000 x104Hertz, and the speed of sound is 343 m/s. At a time of1.5 sec following the release of the platform, the microphone detects a frequency of 9939 Hz. At a time of 3.5 sec following the release of the platform, the microphone detects a frequency of 9857 Hz. Estimate the acceleration of the platform? (assume d constant)