When a car approaches you, the sound waves that reach you have a shorter wavelength and a higher frequency. You hear a sound with a higher pitch. When the car moves away from you, the sound waves that reach you have a longer wavelength and lower frequency.
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An approaching source moves closer during period of the sound wave so the effective wavelength is shortened, giving a higher pitch since the velocity of the wave is unchanged. Similarly the pitch of a receding sound source will be lowered.
The Doppler effect is an effect observed in light and sound waves as they move toward or away from an observer. One simple example of the Doppler effect is the sound of an automobile horn. Picture a person standing on a street corner. A car approaches, blowing its horn.
Comparing two waves of the same wavelength, a higher frequency is associated with faster movement. Comparing two waves of different wavelengths, a higher frequency doesn't always indicate faster movement, although it can. Waves of different wavelengths can have the same frequency.
The pitch of a sound is our ear's response to the frequency of sound. Whereas loudness depends on the energy of the wave. ... The pitch of a sound depends on the frequency while loudness of a sound depends on the amplitude of sound waves.
Answer:
Velocity = 0.309 m/s
Along negative x axis
Explanation:
A pulse moving to the right along the x axis is represented by the wave function
y(x,t) = 2/ (x - 3t)² + 1
At t =0
y(x,0) = 2/ ((x - 3(0))² + 1)
=2 / (x² + 1)
At t = 1
y(x,t) = 2/ ((x - 3(1))² + 1)
= 2 /(( x - 3)² + 1)
At t = 2
y(x,t) = 2/ ((x - 3(2))² + 1)
= 2 /(( x - 6)² + 1)
For the pulse with expression y(x,t) = 4.5
²
The Velocity is
V = 2.7 / 8.73
= 0.309 m/s
Water will evaporate from any
water source and life forms. The answer is letter C. An application of heat
into water will cause the water to evaporate. This is because the
intermolecular forces of attraction of water can be broken by sufficient energy
application.
Answer:
a. 120 W
b. 28.8 N
Explanation:
To a good approximate, the only external force that does work on a cyclist moving on level ground is the force of air resistance. Suppose a cyclist is traveling at 15 km/h on level ground. Assume he is using 480 W of metabolic power.
a. Estimate the amount of power he uses for forward motion.
b. How much force must he exert to overcome the force of air resistance?
(a)
He is 25% efficient, therefore the cyclist will be expending 25% of his power to drive the bicycle forward
Power = efficiency X metabolic power
= 0.25 X 480
= 120 W
(b)
power if force times the velocity
P = Fv
convert 15 km/h to m/s
v = 15 kmph = 4.166 m/s
F = P/v
= 120/4.166
= 28.8 N
definition of terms
power is the rate at which work is done
force is that which changes a body's state of rest or uniform motion in a straight line
velocity is the change in displacement per unit time.
