The gravitational force between two objects can be calculated using Newton's law of universal gravitation:
F = (G * m1 * m2) / r^2
Where:
F is the gravitational force,
G is the gravitational constant (approximately 6.67 x 10^-11 N(m/kg)^2),
m1 and m2 are the masses of the two objects,
r is the distance between their centers.
In this case, we want to calculate the gravitational force between the grapefruit and the Earth while the grapefruit is sitting on the Earth's surface. The mass of the grapefruit (m1) is much smaller than the mass of the Earth (m2), so we can consider the grapefruit's mass negligible compared to the Earth's mass.
The radius of the Earth (r) is approximately 6,371,000 meters (the distance from the Earth's center to its surface).
Now, plug in the values:
F = (6.67 x 10^-11 N(m/kg)^2 * m1 * m2) / (r^2)
F = (6.67 x 10^-11 N(m/kg)^2 * 0.0 kg * 5.972 x 10^24 kg) / (6,371,000 m)^2
F ≈ 9.8 N
the gravitational force between the grapefruit and the Earth is approximately 9.8 Newtons (N).
A. 9.8 N