| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.55 |
| Score | 0% | 71% |
The number system most used in science is the:
American system |
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metric system |
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English system |
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British system |
The metric system is a number system that designates one base unit for each type of measurement. For example, the base unit for length is the meter and the base unit for mass is the gram.
Velocity is the rate at which an object changes position. What is the formula for velocity?
none of these |
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\(\vec{v} = { t \over \vec{d} } \) |
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\(\vec{v} = \vec{d}t \) |
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\(\vec{v} = { \vec{d} \over t } \) |
Velocity is the rate at which an object changes position. Rate is measured in time and position is measured in displacement so the formula for velocity becomes \(\vec{v} = { \vec{d} \over t } \)
The rate of vibration of sound is called:
frequency |
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period |
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volume |
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amplitude |
The rate of vibration of sound is called frequency and is measured in hertz (Hz). One hertz is one repetition per second and sounds with high frequency have a higher pitch than sounds with lower frequency. Humans can hear sounds in the range of 20 Hz to 20 kHz.
Which of the following is not a characteristic of the Sun?
makes up over 99% of the mass of the solar system |
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is composed of hydrogen and helium |
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formed 2.6 billion years ago |
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is a yellow dwarf star |
The Sun is a G-type main-sequence star (G2V) but is informally known as a yellow dwarf star. Composed of 73% hydrogen and 25% helium, the hot plasma that makes up the Sun reaches 9,900°F (5,505°C) at the surface. It formed approximately 4.6 billion years ago and makes up 99.86% of the mass in the solar system.
Which of the following describes how a person's genes express themselves in physical characteristics?
chromotype |
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phenotype |
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genotype |
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DNA |
A person's genotype is their genetic makeup and includes both dominant and recessive alleles. Phenotype is how the genes express themselves in physical characteristics.