The earth's orbit is oval in shape. Explain how the magnitude of the gravitational force between the earth and the sun changes as the earth moves from position 'A' to 'B' as shown in the figure.

Along wire carrying a 4.2 a current perpendicular to the xy-plane intersects the x-axis at x=−1.7cm. a second, parallel wire carrying a 3.0 a current intersects the x-axis at x=+1.7cm. part a at what point on the x-axis is the magnetic field zero if the two currents are in the same direction? express your answer to two significant figures and include the appropriate units.