Earth is the 3rd planet from our Sun at a distance of about 1.50 x 1011 m. Earth has a mass, MEarth, of approximately 6.0 x 1024 kg and a radius, REarth, of about 6,400,000 m. At Earth's surface, a body's weight can be calculated simply by multiplying the body's mass, mbody, by acceleration due to gravity at Earth's surface, g, which is approximately 9.8 m/s2. However, to find the gravitational force exerted by Earth on a body at substantially larger distances from Earth's surface, one would need to use Newton' s Universal Law of Gravitation, shown below, where r represents the distance from the center of Earth to the center of the other body. If the Universal Gravitational Constant, G, is 6.67 x 10-11 N-m2/kg2. PART I. Calculate the force of gravity on a 65-kg person in the following circumstances:

a. At the surface of the Earth (Show all your work.)

b. At twice the Earth's radius (Show all your work.)

c. At four times Earth's radius (Show all your work.)