What frequency is received by a person watching an oncoming ambulance moving at 115 km/h and emitting a steady 753 Hz sound from its siren

77.6 Hz

Explanation:

What frequency is received by a person watching an oncoming ambulance moving at 115 km/h and emitting a steady 753 Hz sound from its siren.

The given parameters are:

Observer speed = 115 km/h

Source frequency = 753 Hz

Speed of sound = 342 m/s

First convert km/h to m/s

Observer speed = (115 × 1000) / 3600

Observer speed = 31.94 m/s

The frequency received by the person will be:

F = fv / ( V - v )

Where

F = frequency received by the person

f = siren frequency

V = speed of sound

v = speed of the ambulance

Substitute all the parameters into the formula

F = (753 × 31.94) / ( 342 - 31.94 )

F = 24050.82 / 310.06

F = 77.568 Hz

Therefore, the frequency received by a person is approximately 77.6Hz

a coal burning power plant

-first use of geothermal energy occurred more than 10,000 years ago in north america by american paleo-indians

-the first industrial use of geothermal energy began near pisa, italy in late 18th century

-in 1904, italian scientist piero ginori conti invented the first geothermal electric power plant in which steam was used to generate the power

-with the above experiment, the first geothermal plant in usa started in 1922 with a capacity of 250 kilowatts

-however, in 1946 first ground-source geothermal heat pump installed at commonwealth building in portland, oregon

-during the 1960’s, pacific gas and electric began operation of first large scale geothermal power plant in san francisco, producing 11 megawatts

-in 1973, when oil crisis began many countries began looking for renewable energy sources and by 1980’s geothermal heat pumps (ghp) started gaining popularity in order to reduce heating and cooling costs

-as effect of climate change started showing results, governments of various countries joined hands to fight against it, for which kyoto protocol was signed in japan in 1997, laid out emission targets for rich countries and required that they transfer funds and technology to developing countries, 184 countries have ratified it

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