A police car moving at 40 m / s chases a thief running away at speed of 30 m / s. The track is perpendicular to a stiff cliff as shown. The police man blows a horn at 40 Hz. If sound has a speed of 340 m / s, what is the beat frequency (in Hz ) heard by the thief?

Question

A police car moving at 40 m / s chases a thief running away at speed of 30 m / s. The track is perpendicular to a stiff cliff as shown. The police man blows a horn at 40 Hz. If sound has a speed of 340 m / s, what is the beat frequency (in Hz ) heard by the thief? (A)  (B)  (C)  (D)

Tardigrade Admin · Accepted Answer

f1=(340-30/340-40) f2=(340+30/340-40) fb=(60/300) × 40=8 Hz

Q. A police car moving at $40 m / s$ chases a thief running away at speed of $30 m / s$ . The track is perpendicular to a stiff cliff as shown. The police man blows a horn at $40 Hz$ . If sound has a speed of $340 m / s$ , what is the beat frequency (in $Hz$ ) heard by the thief?

$f_{1} = \frac{340 - 30}{340 - 40}$
$f_{2} = \frac{340 + 30}{340 - 40}$
$f_{b} = \frac{60}{300} \times 40 = 8 Hz$

Q. A police car moving at 40m/s chases a thief running away at speed of 30m/s. The track is perpendicular to a stiff cliff as shown. The police man blows a horn at 40Hz. If sound has a speed of 340m/s, what is the beat frequency (in Hz ) heard by the thief?

f1​=340−40340−30​ f2​=340−40340+30​ fb​=30060​×40=8Hz

Q. A police car moving at $40 m / s$ chases a thief running away at speed of $30 m / s$ . The track is perpendicular to a stiff cliff as shown. The police man blows a horn at $40 Hz$ . If sound has a speed of $340 m / s$ , what is the beat frequency (in $Hz$ ) heard by the thief?

$f_{1} = \frac{340 - 30}{340 - 40}$
$f_{2} = \frac{340 + 30}{340 - 40}$
$f_{b} = \frac{60}{300} \times 40 = 8 Hz$