| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.43 |
| Score | 0% | 69% |
Water freezing or boiling is an example of which of the following?
phase transition |
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heating |
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sublimation |
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cooling |
A substance undergoes a phase transition when it moves from one state of matter to another, for example, when water freezes or boils.
What part of the nervous system controls simple reflexes?
cerebrum |
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medulla |
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autonomic |
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spinal cord |
The spinal cord connects the brain to the body's network of nerves. It carries impulses between all organs and the brain and controls simple reflexes.
The pitch of the siren of an approaching ambulance changes as it approaches you. This is an example of which of the following?
sound radiation |
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refraction |
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Doppler effect |
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reflection |
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.
Materials like metals that transfer heat efficiently are called:
insulators |
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reflectors |
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refractors |
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conductors |
Heat is always transferred from warmer to cooler environments and conduction is the simplest way this transfer can occur. It is accomplished through direct contact between materials and materials like metals that transfer heat efficiently are called conductors while those that conduct heat poorly, such as plastic, are called insulators.
Force is measured in newtons (N) with 1 N being the force required to impart an acceleration of:
1 mph to a mass of 1 kg |
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1 m/s to a mass of 1 kg |
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1 m/s2 to a mass of 1 kg/s2 |
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1 m/s2 to a mass of 1 kg |
Weight is a force that describes the attraction of gravity on an object. Force is measured in newtons (N) with 1 N being the force required to impart an acceleration of 1 m/s2 to a mass of 1 kg.