Question

1. at dinner, hans passed the salt shaker to his sister jessica by sliding it * 1 po across the wooden table. the salt shaker gradually slowed down and stopped after moving 12 centimeters. why did the salt shaker stop moving?

the salt shaker ran out of force
the table exerts a force that is opposite to the salt shakers motion
the table absorbs force from the salt shaker.
all objects stop moving because their natural state is to be still.

1. force of gravity is directly proportional to *

mass
distance
weight
time

1. as distance between two objects increase the pull of gravity *

increases
stays the same
decreases

Explanation:

18.

According to Newton's first law, an object in motion will stay in motion unless acted upon by an external force. Friction is a force that opposes motion. When the salt shaker slides on the table, the table (due to friction) exerts a force opposite to the salt shaker's motion, which causes it to slow down and stop.

• The first option “The salt shaker ran out of force” is incorrect. Force is not something an object “has” or “runs out of” in the way described. An object's motion is affected by external forces acting on it.
• The third option “The table absorbs force from the salt shaker” is not a correct physical description. It's the frictional force (a contact force that opposes motion) that acts, not “absorbing” force in the described sense.
• The fourth option “All objects stop moving because their natural state is to be still” is contrary to Newton's first law. Objects have a tendency to maintain their state of motion (either at rest or in uniform - motion) unless a net external force acts on them.

The formula for the force of gravity between two objects is \(F = G\frac{m_1m_2}{r^2}\) (where \(G\) is the gravitational constant, \(m_1\) and \(m_2\) are the masses of the two objects, and \(r\) is the distance between their centers of mass). When we consider the gravitational force on an object of mass \(m\) near the Earth's surface (\(F = mg\), where \(g\) is the acceleration due to gravity), we can see that the force of gravity is directly proportional to mass.

• Distance (\(r\)) is in the denominator of the gravitational - force formula (\(F = G\frac{m_1m_2}{r^2}\)), so force of gravity is inversely proportional to the square of the distance.
• Weight (\(W\)) is actually the force of gravity (\(W = F_g\)), so it cannot be that the force of gravity is directly proportional to weight in a non - circular way.
• Time has no direct relation to the formula for the force of gravity.

Using the formula for the gravitational force \(F = G\frac{m_1m_2}{r^2}\), where \(m_1\) and \(m_2\) are the masses of two objects and \(r\) is the distance between them. As \(r\) (the distance) increases, the value of \(F\) (the gravitational force) decreases because we are dividing by a larger number (\(r^2\)).

• If the distance increased and the force increased, it would violate the \(F=\frac{1}{r^{2}}\) relationship in the gravitational - force formula.
• The force does not stay the same. Since \(r\) is changing (and \(m_1\), \(m_2\), and \(G\) are assumed to be constant in a simple two - object non - relativistic case), \(F\) must change.

Answer:

The table exerts a force that is opposite to the salt shaker's motion

19.