Universal Gravitation - College Physics
Card 0 of 3
Two small lead balls of masses 
and 
are fixed a distance 
apart on a laboratory bench. A student moves the larger mass toward the smaller mass so the distance is now only 
. After the mass was moved, by what factor did the gravitational force between the lead balls change?
Two small lead balls of masses
The gravitational force obeys an inverse-square law. Decreasing the distance by a factor of 
will increase the force by a factor of 
, or 
.
The gravitational force obeys an inverse-square law. Decreasing the distance by a factor of
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The gravitational force between two objects is 
. What would be the force of gravity between them if the mass of one of the objects is tripled and the distance between them is doubled?
The gravitational force between two objects is
So the fact that we don't actually know any of the numbers doesn't matter.
What matters is we have the equation 
The masses have a direct proportional relationship with the force. That means that if a mass doubles, the force doubles.
We can also see that the radius (distance between the masses) has an inverse square relationship with Force. So if we double the radius, we divide the force by 4.
So based on the problem, we triple a mass and double the radius. So we triple the force then divide by 4.
So the fact that we don't actually know any of the numbers doesn't matter.
What matters is we have the equation
The masses have a direct proportional relationship with the force. That means that if a mass doubles, the force doubles.
We can also see that the radius (distance between the masses) has an inverse square relationship with Force. So if we double the radius, we divide the force by 4.
So based on the problem, we triple a mass and double the radius. So we triple the force then divide by 4.
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Which of these equations is the universal gravitational equation?
Which of these equations is the universal gravitational equation?
is the equation for Universal gravitation.
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