5ft is two times the 10ft
Answer:
Explanation:
We shall apply concept of Doppler's effect of apparent frequency to this problem . Here observer is moving sometimes towards and sometimes away from the source . When observer moves towards the source , apparent frequency is more than real frequency and when the observer moves away from the source , apparent frequency is less than real frequency . The apparent frequency depends upon velocity of observer . The formula for apparent frequency when observer is going away is as follows .
f = f₀ ( V - v₀ ) / V , f is apparent , f₀ is real frequency , V is velocity of sound and v is velocity of observer .
f will be lowest when v₀ is highest .
velocity of observer is highest when he is at the equilibrium position or at middle point .
So apparent frequency is lowest when observer is at the middle point and going away from the source while swinging to and from before the source of sound .
Answer:
Explanation:
given,
frequency emitted by the speaker(f) = 230 Hz
beat frequency = 1 Hz
speed of the sound (v)= 344 m/s
velocity of the platform = ?
frequency heard by the observer
f_d = 230 Hz + 1 Hz
f_d = 231 Hz
using ,
A is the answer because it is the answer