You are driving on the highway at 40 m/s with another car driving to you at exactly the same speed. when you honk your horn (with a frequency of 315 Hz), what frequency of the sound will the driver of other car perceive. A. 475 hz
B. 235 Hz
C. 315 Hz
D. 7.8 Hz
please give me the answer 30 points+brainliest

You have been hired to design a spring-launched roller coaster thatwill carry two passengers per car. the car goes up a 10-m highhill, then descends 15m to the track's lowest point. you'vedetermined that the spring can be compressed a maximum o 2.0m andthat a loaded car will have a maximum mass of 400kg. for safetyreasons, the spring constant should be 10% larger than the minimumneeded for the car to just make it over the top. a) what spring constant (k) should you specify ? b) what is the maximum speed of a 350 kg car if the spring iscompressed the full amount.