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Home Q & A Board Science-Related Homework Help Physics
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michele12 michele12
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11 years ago
An astronaut lands on a planet that has 4 times the mass of earth and twice the diameter.  The astronaut's mass is 80 kg.  What is the gravitational force exerted by the planet on the astronaut?
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#1
11 years ago
The gravitation is governed directly by mass, and inversely by the square of the distance.  Since the mass is 4 times, and the distance from center of mass is 2*2 greater, the net difference is a factor of 4/4 or 1.  The answer is 80 kg.
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#2
11 years ago Edited: 11 years ago, dmitriych
g=G*m1/r^2   where g is the gravity, G is the gravitational constant, m1 is mass of Earth, r is radius of earth. Increasing mass by a factor of 4 and diameter (or radius) will not change g.
The previous poster was correct in this regard.
Only kg is not the measure of force, it's a measure of mass.
The force is measured in Newtons, therefore you have to multiply the 80kg by 9.8,
The answer is: 784 Newtons
The answer to life, universe and everything is 42 Slight Smile
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