Rank the gravitational forces exerted on the Earth by the following objects.

(basketball, human being, skyscraper, car)

largest to smallest force.

According to newton's law of gravitation, equal force of attraction are applied on two masses m₁ and m₂ placed at distance d. This force is given by the expression

F = G m₁ m₂ / d²

If one of the masses be earth with mass M then d = radius of earth R

Force F = G Mm₁ / R²

this force is applied on both the earth and mass m₁ in equal magnitude and in opposite direction.

In the formula F is proportional to m₁

among the given objects in the question, m₁ of object varies in the following order.

skyscraper > car > human being > basket ball

So Force F on the earth by them will also vary in the same order.