Centripetal Force Directs Inward for Circular Motion

Steps:

• Uniform circular motion requires centripetal acceleration toward the track's center, despite constant speed.
• Resultant force provides this acceleration, per Newton's second law (F = ma).
• Force direction matches acceleration: radially inward.
• Arrow D aligns with the center from the car's position.

Why D is correct:

• Centripetal force is defined as directed toward the center of the circular path (F_c = mv²/r).

Why the others are wrong:

• A points tangential forward, matching velocity, not acceleration.
• B points tangential sideways, unrelated to radial motion.
• C points radially outward, opposing the required inward force.

Final answer: D