Problem: Stars, planets, and moons keep their atmospheres by gravitational attraction, and as such, atmospheres have no clearly delineated boundary: the density of atmospheric gas simply decreases with distance from the object. The Earth's atmospheric pressure drops to about 6998320000000000000♠️3.2102 Pa at 100 kilometres (62 mi) of altitude, the Karman line, which is a common definition of the boundary with outer space. Beyond this line, isotropic gas pressure rapidly becomes insignificant when compared to radiation pressure from the Sun and the dynamic pressure of the solar winds, so the definition of pressure becomes difficult to interpret. The thermosphere in this range has large gradients of pressure, temperature and composition, and varies greatly due to space weather. Astrophysicists prefer to use number density to describe these environments, in units of particles per cubic centimetre.
What is commonly known as the boundary of outer space?
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Answer: the Karman line

Problem: In DC circuits and pulsed circuits, current and voltage reversal are affected by the damping of the system. Voltage reversal is encountered in RLC circuits that are under-damped. The current and voltage reverse direction, forming a harmonic oscillator between the inductance and capacitance. The current and voltage will tend to oscillate and may reverse direction several times, with each peak being lower than the previous, until the system reaches an equilibrium. This is often referred to as ringing. In comparison, critically damped or over-damped systems usually do not experience a voltage reversal. Reversal is also encountered in AC circuits, where the peak current will be equal in each direction.
When a system is over-damped, what does it typically not experience?
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Answer: a voltage reversal

Problem: During the 19th century, Karl Marx and Friedrich Engels extended the concept of materialism to elaborate a materialist conception of history centered on the roughly empirical world of human activity (practice, including labor) and the institutions created, reproduced, or destroyed by that activity (see materialist conception of history). Later Marxists developed the notion of dialectical materialism which characterized later Marxist philosophy and method.
What type of materialism did not define the Marxist philosophy?
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Answer:
unanswerable