4. Two charged spheres are on a friction-less horizontal surface. One has a charge of +3.0 x 10-6 C, the other a +6.0 x 10-6 C charge. Sketch the two spheres, showing all forces on them. Make the length of your force arrows proportional to the strength of the forces. 5. The Earth rotates around the Sun in part because of the gravitational attraction between them. The Earth has a mass of 5.98 x10" kg and the Sun has a mass of 1.99 x1030 kg. The average distance between the sun and the Earth is 1.5 x10" m. a. Draw a force diagram for each object. b. Solve for the magnitude of the gravitational force that each object exerts on the other. C. Calculate the magnitude of the gravitational force of one on the other when their separation is reduced by a factor of 10. 6. A 75 kg man is standing on the surface of the Earth. The Earth has a mass of 5.98 x1024 kg and a radius of 6.38 x10 m. Assume all of the mass of the Earth can be concentrated at its center. a. Calculate the force of attraction between the man and the Earth. b. Divide your answer for part (a) by the mass of the man. c. Your answer to part (b) should be interesting. Explain how your answer is not a mathematical coincidence