Question

Leo drew a force diagram to represent a satellite in orbit around Earth.

An illustration of the earth with a vector north labeled F Subscript air Baseline and a vector south labeled F Subscript g Baseline. Both vectors are same length.
Which best explains how to correct Leo’s diagram?

make the Fg vector longer
change the vector labeled Fair so it is labeled Fp
add an Fp vector at the center and pointing left
remove the Fair vector

Answer 1

Remove the Fair vector.

A satellite in orbit is essentially in free fall — there is no significant air force acting on it, so gravity (Fg) toward Earth's center is the only major force. Showing equal opposite forces would imply no net force (no centripetal acceleration), which is wrong for an orbiting satellite.