Gravitational Force in Orbit

Steps:

• Identify the force acting on the ISS: gravitational attraction from Earth.
• Determine the direction: always towards Earth's center, providing centripetal force for orbit.
• Locate point X: assume it's a position in circular orbit around Earth.
• Match arrow to direction: select the one pointing radially inward toward Earth.

Why A is correct:

• Arrow A points toward Earth's center, aligning with Newton's law of universal gravitation, where force direction is along the line connecting the masses.

Why the others are wrong:

• B points radially outward, confusing gravity with centrifugal force, which is fictitious.
• C points tangentially, matching orbital velocity direction, not force.
• D points opposite to gravity, implying repulsion, which doesn't apply here.

Final answer: A