<span>Answer: "a cold front" .
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Answer: C. 12.6
Explanation: 2*pi*1.8= 11.304
11.304/0.9= 12.56
Answer:

Explanation:
The intensity is related to the power and surface area by
. We need to calculate the surface area of a sphere of radius r=4.3ly.
Since 4.3ly is the distance light travels in 4.3 years at 299792458m/s, we can obtain it in meters by doing:

So we have:

Answer:
Almost all machines require energy to offset the effects of gravity, friction, and air/wind resistance. Thus, no machine can continually operate at 100 percent efficiency.
Answer:
a)
, b) 
Explanation:
a) According to the First Law of Thermodinamics, the system is not reporting any work, mass or heat interactions. Besides, let consider that such box is rigid and, therefore, heat contained inside is the consequence of internal energy.

The internal energy for a monoatomic ideal gas is:

Let assume that cubical box contains just one kilomole of monoatomic gas. Then, the temperature is determined from the Equation of State for Ideal Gases:



The thermal energy contained by the gas is:


b) The physical model for the cat is constructed from Work-Energy Theorem:

The speed of the cat is obtained by isolating the respective variable and the replacement of every known variable by numerical values:


