A car with a mass of 1,500 kg requires a centripetal force of 640 N to safely follow a circular curve in the road at 13.4 m/s.

Centripetal force is given by F = mv²/r, so rearrange to find the curve’s radius: r = mv²/F. Substituting the values gives r = (1,500 kg)(13.4 m/s)² ÷ 640 N ≈ 420.8 m. Rounded to the nearest meter, the radius is 421 m, choice C.

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