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Unformatted text preview: iversal Gravitation. If we
consider the force of gravity mass to the left of the origin acting on the mass at the origin: Now, we consider the force of gravity to the right of the origin acting on the mass at the origin: Since the masses are equivalent weight, it makes sense that the closest mass to the origin exerts
the greater force of the two. Thus, we know that the force is acting to the left of the origin, and to get
the magnitude of the net gravitation force, we take the difference of the two: b. As stated before, the force is acting to the left.
Problem 4)
a. We can set up the equation as following: we know the distance of the center of the earth to the
center of the moon (REM=3.84 x 108), so we will set up a variable r such that r is the distance the
spaceship needs to be from the center of the earth so that it experiences a force twice that from Earth
than it does from the moon. Conveniently, the mass of the ship cancels out. Rearranging such that the r’s are all on one side, we get
that: This equation is conveniently in the form of the Pythagorean Theorem. Thus, we can solve: Only one of these answers satisfies the condition where the spaceship is between the Earth and Moon,
the first one. b. The answer is independent of the mass of the spaceship because we end up cancelling out the mass
anyway. Problem 5)
a. The only mass units are in units of kg or derivative units (g, dg, …): .34 g, 120 kg
b. The only force units are Newtons (S.I.) and pounds (Imperial): 12 lb, 1600 kN
c. Mass is invariant while weight is not. Thus, only the weight changes. d. As before, the mass is invariant. However, since we are increasing the distance between an object and
the planet, we are decreasing the force of gravity and therefore decreasing the weight. Problem 6)
a. No, astronauts do not experience weightlessness because they are beyond the pull of Earth’s gravity,
but rather because they are in f...
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This homework help was uploaded on 04/02/2014 for the course PHYSICS 6b taught by Professor Staff during the Spring '11 term at UCSB.
 Spring '11
 Staff
 Force, Gravity, Work

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