Forces on a Falling Object: Gravity and Air Resistance

Steps:

• Identify all forces: gravitational force downward, air resistance upward opposing velocity.
• Apply Newton's first law: forces must balance directionally for vertical fall.
• Consider motion: object accelerates downward, so net force is downward.
• Select diagram showing only these two forces with gravity larger than resistance.

Why A is correct:

• Depicts gravitational force (weight, mg) downward and air resistance upward, per Newton's second law (net force = ma, with downward acceleration).

Why the others are wrong:

• B shows only gravity, ignoring air resistance as a real force on objects in air.
• C includes horizontal force, irrelevant for vertical fall.
• D shows equal forces, implying no acceleration, contradicting free fall.

Final answer: A