Question

PRINTER VERSION 4 BACK NEXT ES Chapter 24, Problem 19 A lidar (laser radar) gun is an alternative to the standard radar gun that uses the Doppler effect to catch speeders. A lidar gun uses an infrared laser and emits a precisely timed series of pulses of infrared electromagnetic waves. The time for each pulse to travel to the speeding vehicle and return to the gun is measured. In one situation a lidar gun is a stationary police car observes a difference of 1.11 x 10's in round-trip travel times for two pulses that are emitted 0.540 s apart. Assuming that the speeding vehicle is approaching the police car essentially head-on, determine the speed of the vehicle. 3 di 2 B Number Units ly the tolerance is +/-2% Click if you would like to show Work for this question: Oren Show Work By accessina this Ouestion Assistance, vou will learn while vou earn points based on the Point Potential Policy set bv vour instructor. Next MacBook Pro DII DD FVO 1 12 +

Answer 1

given, police car difference in lime of an soemel toip, t₂nt, in 1-11x10" observed I by Palice Time of emêt of pulse, tpulse 0. 540 & [speeding vahele • approcching the police com] Let the distance covered by pulse, in a time the gover by -o l specod of light e as a sound trip of ad a covend in in time it Cas infrared levels with ad=ct d t co d= ct 2 How the distance travelled by the speeding vehicle towards the palice can in the enfermeel of two pulses in given by D- dard, where, da che and dotti di = ct where, and to are the time of pulse emited. subske tuting these in above equation D= dard = ctz chi ç (82 - ) 2 E D = ( ht) now, the moment the pulse ermitted and does a speeding vehicle sound trip, the speed given by distance travelled by behicle D VA tpulse time of pulse for that distance 30 speed of the speeding vehicle. C (Art) (3x18 r) (1. X10~46) 2 epulse (2)(0.5408) 30. 83 morbo VE

Comment

The speed of the speeding vehicle was found to be 30.83m/s