Which of the following is an equation for gravitational force?

The equation for gravitational force is defined as F = mg, where F represents the gravitational force, m is the mass of the object, and g is the acceleration due to gravity, typically approximated as 9.81 m/s² on the surface of the Earth. This equation expresses how the force experienced by an object is directly proportional to its mass and the constant acceleration of gravity.

In this context, the gravitational force acts as a pulling force that attracts two masses together, with the mass of the Earth being one of the masses involved in this interaction. Understanding this relationship is crucial in physics, as it allows for the calculation of the weight of an object, which is essentially the force of gravity acting on it. The other options involve different physical concepts or laws, which do not represent gravitational force specifically. For instance, F = ma is Newton's second law for any force resulting from acceleration, while F = 1/2mv² relates to kinetic energy, and F = dp/dt describes the change in momentum over time.