Contrasting the Doppler effect with shock waves, the one that requires the faster source is?

Physics

2 answers:

MAXImum [283]3 years ago

6 0

I think shock waves require more speed they travel at the speed of sound

WITCHER [35]3 years ago

5 0

Answer:

Shock waves

Explanation:

The Doppler effect is well noticed at moments where the speed of the source is going slower than the speed of the waves. E.g. the change in apparent frequency of the sound of a train horn. As the train nears the observer, the blast of its horn is observed at a high pitch and as the train accelerates further, the blast of its horn is observed at a low pitch.

A shock wave is observed if the source is going at an equal speed as or faster than the wave can go. When the origin of sound moves at an equal speed as sound, it results in the source being at the front edge of the waves that it forms at all times.

The attached image shows a snapshots in time of diverse wavefronts forned by an aircraft that is accelerating at an equal speed as sound. The circular lines represent compressional wavefronts of the sound waves. Notice that these circles are bunched up at the front of the aircraft. This phenomenon is known as a shock wave. Shock waves are also produced if the aircraft moves faster than the speed of sound. If a moving source of sound moves faster than sound, the source will always be ahead of the waves that it produces. The diagram at the right depicts snapshots in time of a variety of wavefronts produced by an aircraft that is moving faster than sound. Note that the circular compressional wavefronts fall behind the faster moving aircraft (in actuality, these circles would be spheres).

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Explanation:

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initial momentum = 100 x 15 = 1500kgm/s

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a =(v-u)/t

a = (20-15)/10

a = 5/10

a = 0.5m/s²

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7 0

3 years ago

The auto in the sketch moves forward as the brakes are applied. A bystander says that during the interval of braking, the auto's

Ivan

Answer:

The statement is true: velocity and acceleration have opposite directions in the interval of braking.

Explanation:

Let's say we have a velocity $v>0$ .

The acceleration $a$ is the rate of change of the velocity $v$ . This means that if $v$ is <em>increasing during</em> time, then $a$ must be positive. But if $v$ is <em>decreasing over</em> time, then $a$ will be negative (even though the velocity is positive).