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 in a stationary police car observes a difference of 1.27 × 10−7 s in round-trip travel times for two pulses that are emitted 0.450 s apart. Assuming that the speeding vehicle is approaching the police car essentially head-on, determine the speed of the vehicle.

Respuesta :

Answer:

v = 42.33 m/s

Explanation:

The time difference between two pulses that are emitted by Police is observed in the interval

[tex]\Delta t = 1.27 \times 10^{-7} s[/tex]

now the speed of the electromagnetic wave is given as

[tex]c = 3 \times 10^8 m/s[/tex]

now the distance traveled by them

[tex]d = c \times t[/tex]

[tex]d = (3 \times 10^8)(1.27 \times 10^{-7})[/tex]

[tex]d = 38.1 m[/tex]

so distance of speeding vehicle covered for round trip of wave is 38.1 m

now for one trip it is given as d = 19.05 m

now the speed of the vehicle is given as

[tex]v = \frac{d}{t}[/tex]

[tex]v = \frac{19.05}{0.450}[/tex]

[tex]v = 42.33 m/s[/tex]

The speed of the vehicle, is[tex]41.34m/s.[/tex]

What is speed?

The speed of an object serves as  magnitude of the rate of change of its position with time.

Speed can be calculated as[tex]C= d/ t[/tex]

where [tex]C= speed= 3*10^8 m/s[/tex]

t= time

d= distance

The time interval between two pulses by the police= 1.27*10^-7 s.

[tex]Distance= ( 3*10^8 * 1.27*10^-7)= 38.1m[/tex]

To know distance traveled for a trip we will divide the distance traveled for a cycle which is [tex](38.1/2)= 19.05m[/tex][tex](38.1 /2) = 19.05m[/tex]

Then the speed of the vehicle can be calculated as C= d/ t

Where[tex]C= 19.05/0.450= 41.34m/s[/tex]

Therefore, speed of the vehicle, is [tex]41.34m/s.[/tex]

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