Question

The beat detected on a moving platform.

A speaker fixed to a moving platform moves toward a wall, emitting a steady sound with a frequency of 230 Hz . A person on the platform right next to the speaker detects the sound waves reflected off the wall and those emitted by the speaker.

Part A.) How fast should the platform move, vp, for the person to detect a beat frequency of 2.00 Hz? Take the speed of sound to be 344 m/s. Express your answer numerically in meters per second using three significant figures.

Could someone show me how I could solve this? Thank you!

Constants Periodic Table Part A A speaker fixed to a moving platform moves toward a wall, emitting a steady sound with a frequency of 230 Hz. A person on the platform right next to the speaker detects the sound waves reflected off the wall and those emitted by the speaker. How fast should the platform move, up, for the person to detect a beat frequency of 2.00 Hz ? Take the speed of sound to be 344 m/s. Express your answer numerically in meters per second using three significant figures. View Available Hint(s) p0.745 SubmitPre > Incorrect; Try Again; 29 attempts remaining ious Ans Provide Feedback Next >

Answer 1

Beta frequency = 2 Hz reflected Doppler frequency f_d = 230 + 2 = 232 Hz f_d = f(V + v_r)/V - V_p {V_r = V_p} 232 = 230 (344 + V_p/344 - v_p) 346.99 - 1.008696 V_p = 344 + v_p 2.99 = 2.008696 v_p v_p = 1.5 m/s