To determine which picture shows the least gravitational force, we need to consider two factors: the masses of the objects and the distance between them. According to the law of universal gravitation, the gravitational force (F) between two objects is given by the equation:
\[ F = G \frac{{m_1 m_2}}{{r^2}} \]
Where:
- \( F \) is the gravitational force,
- \( G \) is the gravitational constant,
- \( m_1 \) and \( m_2 \) are the masses of the two objects, and
- \( r \) is the distance between the centers of the two masses.
From this formula, we can glean that:
- Greater mass results in a greater gravitational force.
- Greater distance results in a lesser gravitational force (since force is inversely proportional to the square of the distance).
Given this information, the picture that shows the least gravitational force would be the one with smaller masses and larger distances between the objects.
Therefore, the correct response would be:
Picture IV because the objects have smaller mass and larger distance between them.