Abaseball hits a car, breaking its window and triggering its alarm which sounds at a frequency of 1210 hz. what frequency (in hz) is heard by a boy on a bicycle riding away from the car at 8.25 m/s? take the speed of sound to be 343 m/s.

The frequency of sound heard by the boy is 1181 Hz.

Explanation:

Given that,

Frequency of sound from alarm  

Speed = -8.25 m/s

Negative sign show the boy riding away from the car

Speed of sound = 343

We need to calculate the heard frequency

Using formula of frequency

Where, = frequency of source

= speed of observer

= speed of source

= speed of sound

Put the value into the formula

here, source is at rest

Hence, The frequency of sound heard by the boy is 1181 Hz.

the average speed is 24.57 km/hr

when a device is used in a circuit in which the voltage is 81 v, the current flowing through the device is 3 a. what is the resistance of the device?

a. 27 ω

b. 40.5 a

c. 243 ω

d. 243 a

the correct answer is a. 27