A remote-controlled plane has a mass of 0.386 kg and flies in a circle with a radius of 75 m. The centripetal force on the plane is 4.0 N.

Use the centripetal-force equation, F = mv²/r, and solve for speed: v = √(Fr/m). Substituting the values gives v = √[(4.0 N)(75 m)/(0.386 kg)] ≈ 27.9 m/s. Therefore, the plane’s speed is 28 m/s, choice B.

AI-written and checked against the verified answer.