You are designing an autonomous electric car to transport goods on campus. As you are worried about cost, you are thinking about whether to use a laser scanner or an ultra-sound sensor for detecting obstacles. As you drive rather slow, you are required to sense up to 15 meters. The laser scanner you are considering can sense up to this range and has a bandwidth of 10Hz. a. Calculate the time it takes until you hear back from the ultrasonic sensor when detecting an obstacle 15m away. Assume that the robot is not moving at this point. Use = 300/ for the speed of sound. b. Calculate the time it takes until you hear back from the laser scanner. (Hint: You do not need the speed of light to answer this question)