| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.24 |
| Score | 0% | 65% |
The pitch of the siren of an approaching ambulance changes as it approaches you. This is an example of which of the following?
reflection |
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sound radiation |
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refraction |
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Doppler effect |
The Doppler effect occurs when the source or listener (or both) of sound waves is moving. If they're moving closer together, the listener perceives the sound with a higher pitch and, when they're moving apart, the listener perceives the sound with a lower pitch.
Blood pressure is generally highest in which of the following?
heart |
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veins |
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arteries |
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capillaries |
Arteries are thick-walled because they carry oxygenated blood at high pressure, veins are comparatively thin-walled as they carry low-pressure deoxygenated blood.
An asteroid belt holds many of the asteroids in our solar system. It is located between the orbits of which planets?
Mars and Earth |
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Mercury and Venus |
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Mars and Jupiter |
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Jupiter and Saturn |
The solar system also contains over a million rocky fragments of at least 1km in diameter called asteroids as well as millions more with smaller diameters. Many of these asteroids are an asteroid belt between the orbits of Mars and Jupiter.
These clouds grow upward and can develop into cumulonimbus or thunderstorm clouds.
stratus clouds |
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cumulus clouds |
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cirrus clouds |
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nimbus clouds |
Cumulus clouds are large, puffy, mid-altitude clouds with a flat base and a rounded top. These clouds grow upward and can develop into a cumulonimbus or thunderstorm cloud.
"The acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object." This describes which of Newton's laws of motion?
first |
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second |
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third |
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fourth |
Newton's second law of motion states that The acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object. This law basically means that the greater the mass of an object, the more force is needed to overcome its inertia.