3. A source emitting a sound at 300.0 Hz is moving toward an observer at 25m/s The air temperature is 15^circ C What is the frequency detected by the observer? K/U

Here's how to calculate the frequency detected by the observer:<br /><br />**1. Determine the speed of sound in air:**<br /><br />The speed of sound in air is temperature-dependent and can be calculated using the formula:<br /><br />v = 331 m/s + (0.6 m/s/°C) * T<br /><br />Where:<br />* v is the speed of sound<br />* T is the air temperature in Celsius<br /><br />In this case, T = 15°C, so:<br /><br />v = 331 m/s + (0.6 m/s/°C) * 15°C = 340 m/s<br /><br />**2. Apply the Doppler effect formula:**<br /><br />The Doppler effect formula for a moving source and a stationary observer is:<br /><br />f' = f * (v / (v - vs))<br /><br />Where:<br />* f' is the observed frequency<br />* f is the source frequency<br />* v is the speed of sound<br />* vs is the speed of the source (positive if moving towards the observer)<br /><br />**3. Plug in the values and solve:**<br /><br />f' = 300.0 Hz * (340 m/s / (340 m/s - 25 m/s))<br />f' = 300.0 Hz * (340 m/s / 315 m/s)<br />f' ≈ 323.8 Hz<br /><br />**Answer:** The frequency detected by the observer is approximately 323.8 Hz.<br />