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, vp , for the person to detect a beat frequency of 5.00 Hz ?

Take the speed of sound to be 344 m/s .

Express your answer numerically in meters per second using three significant figures.

In triangle abc segment de is parallel to the side ac . (the endpoints of segment de lie on the sides ab and bc respectively). find de, if ac=20cm, ab=17cm, and bd=11.9cm;

According to the 2008 u.s. census, california had a population of approximately 4 × 10^7 people and florida had a population of approximately 2 × 10^7 people. which of the following is true? a. the population of florida was approximately two times the population of california. b. the population of florida was approximately twenty times the population of california. c. the population of california was approximately twenty times the population of florida. d. the population of california was approximately two times the population of florida.

26) -2(7x) = (-2 • 7) x a. associative property of addition b. associative property of multiplication c. commutative property of multiplication d. commutative property of addition