Question

Question #f2899

Answer 1

The magnitude of the force of gravity acting on an object depends on its mass, not its size. For example, we would expect a pen to weigh more than a piece of tissue paper, even though the paper has a greater surface area, or size.

The weight of a stationary object is given by the force of gravity acting upon it, where `W=F_g=mg`. We can see from this formula that the force of gravity acting on a stationary object depends only on the mass of the object, which is multiplied by the gravitational (free-fall) acceleration constant, `g`.

Newton's law of universal gravitation, which describes gravitational force between two bodies, is given by:

`F=G(m_1m_2)/r`

Again, we can see there is no variable accounting for the size of the object, but mass is a crucial component in the calculation.

Of course, we can also see that the calculation depends on the distance between the objects. For the weight of a stationary object on Earth (`F_g=mg`), we assume the object is at or near the surface of the planet.