The gravitational force acting on an object on the Earth's surface is its weight. To calculate the weight, we use the following formula:

Weight (W) = Mass (m) * Acceleration due to gravity (g)

Here's what we know:

* Mass (m) = 70.0 kg

* Acceleration due to gravity (g) = 9.81 m/s² (approximately)

Now, let's plug in the values:

W = 70.0 kg * 9.81 m/s²

W = 686.7 N

Therefore, the gravitational force acting on the 70.0 kg object standing on the surface of the Earth is approximately 686.7 Newtons.