A 0.50 kg ball moves in a horizontal circle of radius 2.0 m at a constant speed of 4.0 m/s. What centripetal force acts on it?
Answer and explanation
Correct answer: C. 4.0 N
- Step 1: F = mv^2 / r. Step 2. F = 0.50 x 4.0^2 / 2.0 = 0.50 x 16 / 2.0 = 4.0 N. Answer: 4.0 N. Why not the others: 1.0 N uses v instead of v^2, 8.0 N leaves out the division by the radius, and 16 N multiplies by the radius instead of dividing.
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