UNIVERSE
SOLAR SYSTEM FORMATION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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slower
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faster
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constant
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variable
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Detailed explanation-1: -A planet moves slower when it is farther from the Sun because its angular momentum does not change. For a circular orbit, the angular momentum is equal to the mass of the planet (m) times the distance of the planet from the Sun (d) times the velocity of the planet (v).
Detailed explanation-2: -On July 4, 2011, when the Earth was farthest from the Sun (aphelion, 152.1 million kilometers) it was traveling at 29.3 km/s.
Detailed explanation-3: -The orbital period increases if the orbital distance is increased.
Detailed explanation-4: -The closer a planet is to the Sun, the less time it takes for it to go around the Sun. It takes less time because the length of the orbit is shorter (a smaller orbit), but it also moves faster in its orbit. Thanks to gravity, it has to move faster in its orbit to stay in orbit!