A police car is approaching at a speed of 20.0 m/s with its siren emitting a frequency of 1.0 kHz. What frequency does a stationary observer detect? The speed of sound in this case is 330 m/s.

The intensity, or loudness, of a sound can be measured in decibels (db), according to the equation , where i is the intensity of a given sound and is the threshold of hearing intensity. what is the intensity, in decibels, [i(db)], when ? use a calculator. round to the nearest whole number. 8 9 19 80

Asun-sized star will spend most of its lifetime as a: white dwarf red giant protostar main-sequence star

In a system, when potential energy decreases, then entropy also decreases. true false