Answer:
In a controlled experiment, an independent variable (the cause) is systematically manipulated and the dependent variable (the effect) is measured; any extraneous variables are controlled. The researcher can operationalize (i.e. define) the variables being studied so they can be objectivity measured.
Given the distance traveled and time elapsed, the average speed of the train is approximately 26.944m/s.
<h3>What is the average speed of the train?</h3>
Speed is simply referred to as distance traveled per unit time.
Mathematically, Speed = Distance ÷ time.
Given the data in the question;
- Distance traveled = 221miles
- Elapsed time = 3 hours and 40 minutes
First we convert miles to meters and Hours minutes to seconds.
221 miles = ( 221 × 1609.344 )m = 355665.024 meters
3 hours and 40 minutes = ( 3×60×60)s + ( 40×60)s
= 10800s + 2400s
= 13200s
Now, determine the average speed.
Speed = Distance ÷ time
Speed = 355665.024m / 13200s
Speed = 26.944m/s
Given the distance traveled and time elapsed, the average speed of the train is approximately 26.944m/s.
Learn more about speed here: brainly.com/question/7359669
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Answer: The answer: The car is moving away from you.
Both A and C are true as Car can be moving in line away from you or has component of velocity in opposite direction.
Explanation:The decrease in the frequency of the sound is the result of Doppler's effect. A/c to Doppler's effect the frequency of received sound of source is changed if it is moving relative to the receiver, i.e. the distance between them is changing due to motion.
The general formula of Doppler's Effect is attached as the picture.
In this formula v_D is the velocity of Detector i.e the receiver relative to wind. While v_s is the velocity of source relative to wind and v is the velocity of sound.
The Doppler's effect is not effected by the velocity of wind as the wind itself could not change the distance between the two objects i.e. you and the car. Wind velocity can change the speed of sound and its wavelength but the change does not effect the frequency.
Hence if we assume the car to be moving with velocity v_c and you are stationary
hence the frequency is reduced.