a siren on top of the police car emits sound at frequency of 820 Hz. The car passed a bystander on a sidewalk and is receding at speed 142 km/h/ what is the frequency the bystander hears. assume the speed of sound in air to be 340 m/s.
142 km/h x 1000 / 3600 = 39.44 m/s
fo=fs (v+-vo/v+-vs)
fo= 823 hz (340/340+39.44) = 737.45 m/s
so i have the answer, i just need to know what 142 is multiplied by 1000 then divided by 3600 to equal 39.44 m/s
Vs = 142,000m/3600s = 39.44 m/s.
3600s = 1 hour.
142km = 142,000 m.
To convert 142 km/h to m/s, you need to multiply it by 1000 and then divide by 3600. Here's a step-by-step breakdown:
1. Start with 142 km/h.
2. To convert km to meters, multiply by 1000.
142 km/h * 1000 = 142000 m/h.
3. To convert hours to seconds, divide by 3600.
142000 m/h / 3600 = 39.44 m/s.
So, multiplying 142 by 1000 and dividing by 3600 gives you a speed of 39.44 m/s.