At an auto race, a member of the pit crew stands beside the track. a car approaches him at 100 m/s and emits a sound at frequency 1100hz. the air is still and the speed of sound is 340mls. what frequency will the pit crew member hear? a.1560hz b.1420hz c.1640hz d.850hz

A. 1560 Hz

Explanation:

The Doppler effect occur when a source of a wave (like sound) is moving relative to an observer (or when the observer is moving relative to the source). When this happens, the apparent frequency of the sound as heard by the observer is shifted with respect to the real frequency, according to the formula:

where

f' is the apparent frequency

v is the speed of the wave

vs is the velocity of the source relative to the observer (positive if the source is moving towards the observer, negative if it is moving away from the observer)

f is the real frequency of the wave

In this problem, we have the following data:

f = 1100 Hz is the original frequency of the sound

v = 340 m/s is the speed of the sound wave

is the velocity of the car approaching the pit crew

Substituting these numbers into the formula, we can find the frequency heard by the pit crew:

answer: 802.3 kilo joules of energy represents 191.75 kilo calorie of energy.

explanation:

energy released during combustion of one mole methane = 802.3 kilo joules

if 1 kilo joule = 0.239006   kilo calorie

then ,802.3 kilo joule will be = 802.30.239006 kilo calorie

802.3 kilo joule = 191.75 kilo calorie

hence, the energy in kilo calorie is 191.75 kilo calorie.