The radar system associated with the automatic doors at a local grocery store uses 10.5 gigahertz radiation. If the door is to open for a person walking towards it at 1 meter per second, which Doppler shift must the radar system be able to detect:

W) a red shift of 2 hertz

X) a blue shift of 35 hertz

Y) a red shift of 160 hertz

Z) a blue shift of 1.8 hertz
X) A BLUE SHIFT OF 35 HERTZ