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Electronics Information

Which of the following will help to prevent a short circuit?

fuse

Fuses are thin wires that melt when the current in a circuit exceeds a preset amount. They help prevent short circuits from damaging circuit components when an unusually large current is applied to the circuit, either through component failure or spikes in applied voltage.

Arithmetic Reasoning

What is \( 5 \)\( \sqrt{28} \) + \( 7 \)\( \sqrt{7} \)

17\( \sqrt{7} \)

To add these radicals together their radicands must be the same:

5\( \sqrt{28} \) + 7\( \sqrt{7} \)
5\( \sqrt{4 \times 7} \) + 7\( \sqrt{7} \)
5\( \sqrt{2^2 \times 7} \) + 7\( \sqrt{7} \)
(5)(2)\( \sqrt{7} \) + 7\( \sqrt{7} \)
10\( \sqrt{7} \) + 7\( \sqrt{7} \)

Now that the radicands are identical, you can add them together:

10\( \sqrt{7} \) + 7\( \sqrt{7} \)
(10 + 7)\( \sqrt{7} \)
17\( \sqrt{7} \)

General Science

__________ is caused by a lack of iron in the diet.

anemia

Anemia, which may cause weakness, dizziness, and headaches is caused by a lack of iron in the diet.

Math Knowledge

The dimensions of this cylinder are height (h) = 5 and radius (r) = 4. What is the surface area?

72π

The surface area of a cylinder is 2πr² + 2πrh:

sa = 2πr² + 2πrh
sa = 2π(4²) + 2π(4 x 5)
sa = 2π(16) + 2π(20)
sa = (2 x 16)π + (2 x 20)π
sa = 32π + 40π
sa = 72π

General Science

A biological community of interacting organisms and their physical environment is known as:

ecosystem

An ecosystem is a biological community of interacting organisms and their physical environment. This includes both the biotic (living) and abiotic (non-living).

General Science

The Earth's rocks fall into three categories based on how they're formed. Which of the following is formed when existing rock is altered through pressure, temperature, or chemical processes?

metamorphic

The Earth's rocks fall into three categories based on how they're formed. Igneous rock (granite, basalt, obsidian) is formed from the hardening of molten rock (lava), sedimentary rock (shale, sandstone, coal) is formed by the gradual despositing and cementing of rock and other debris, and metamorphic rock (marble, slate, quartzite) which is formed when existing rock is altered though pressure, temperature, or chemical processes.

Mechanical Comprehension

How much work can a 1 hp engine do in 3 seconds?

1650 ft⋅lb

Horsepower (hp) is a common measure of power output for complex machines. By definition, a 1 hp machine does 550 ft⋅lb of work in 1 second: 1 hp = 550 ft⋅lb/s. Substituting the variables for this problem gives us:
\( W = 1 hp \times 550 \frac{ft⋅lb}{s} \times 3s = 1650 ft⋅lb \)

General Science

Which of the following would be used in eye glasses to correct nearsightedness?

concave lens

Unlike curved mirrors that operate on the principle of reflection, lenses utilize refraction. A convex lens is thicker in the middle than on the edges and converges light while a concave lens is thicker on the edges than in the middle and diffuses light. A common use for curved lenses is in eye glasses where a convex lens is used to correct farsightedness and a concave lens is used to correct nearsightedness.

General Science

The hottest of Earth's atmospheric layers is which of the following?

thermosphere

Temperatures again increase with altitude in the thermosphere which is the hottest (4,530 °F / 2,500 °C) atmospheric layer due to direct exposure to the Sun's radiation. However, the gas in this layer is highly diluted so even though the atoms of gas may be very high in temperature, there are too few of them to effectively transfer much heat.

Electronics Information

The watt is a unit of measurement for:

power

Electrical power is measured in watts (W) and is calculated by multiplying the voltage (V) applied to a circuit by the resulting current (I) that flows in the circuit: P = IV. In addition to measuring production capacity, power also measures the rate of energy consumption and many loads are rated for their consumption capacity. For example, a 60W lightbulb utilizes 60W of energy to produce the equivalent of 60W of heat and light energy.