Answer:
A sound wave is called a longitudinal wave because compressions and rarefactions in the air produce it. The air particles vibrate parallel to the direction of propagation.
Frequency is defined as the number of repetitions of waves occurring in 1 second. The frequency heard by the man as the ambulance move toward him will be greater than 450 Hz.
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What is the frequency ?</h3>
Frequency is defined as the number of cycles completed in 1 second. Frequency is given by the formula as,

As the formula shows frequency is inversely proportional to the time that shows if the time is decreasing frequency will increase and vice versa.
In the above case, the ambulance is moving toward the men. So that the time to meet up is decreased that's why the frequency will be greater than the initial frequency from the siren.
Hence the frequency heard by the man as the ambulance move toward him will be greater than 450 Hz.
To learn more about frequency refer to the link ;
brainly.com/question/4393505
Answer:
Since it us the resistance that causes the power output, it might be intuitive to think that more resistance produces more power but as P=I^2 * R one actually needs high current and low resistqnce. That means 75 W has lower resistance and higher current.
Now you may think that making the resistance very low, one gets the most power. Not so, as the circuit has wires, power source etc. All the have their resistance. In theory one gets the maximum power over a resistor when the resistor is half of the total resistance of the circuit. This in practice would be inefficient as one would lose half of the total power elsewhere. In practice circuits have fuses that limit the current and one gets the maximum power at the current the fuse is rated to. So if there is 20 A fuse, the maximum power is 2400 W and the corresponding resistance 6 ohm.
Answer:
.17Hz
Explanation:
The formula for frequency is f= 1/T , where T is the period.
f = 1/6 and 1/6 ≈ .17
Answer:
Static stretching.
Explanation:
It is static stretching because it is a form of stretching which u can do actively for a period of time and you hold position for about 30 to 60 seconds which allow the muscles and connective tissues to lengthen. It is done after work out with out movement in order to loosen up muscles so as to gain flexibility.