Physics

Physics

Problem

A car travels round a horizontal circular track of radius 50 m50\,\text{m} at a constant speed of 10 m s−110\,\text{m s}^{-1}. The magnitude of its acceleration is a) 0.2 m s−20.2\,\text{m s}^{-2} b) 20 m s−220\,\text{m s}^{-2} c) 2 m s−22\,\text{m s}^{-2} d) 4 m s−24\,\text{m s}^{-2}
Intuitive explanation

Circular motion at constant speed is all about centripetal acceleration—the car isn't speeding up or slowing down, but it's constantly changing direction, which requires a net force toward the center. The key insight is that this acceleration depends only on how fast you're going and how tight the curve is, captured by the formula a=v2ra = \frac{v^2}{r}. Plug in your speed and radius, and you've got the answer.

Intuitive explanation

Circular motion at constant speed is all about centripetal acceleration—the car isn't speeding up or slowing down, but it's constantly changing direction, which requires a net force toward the center. The key insight is that this acceleration depends only on how fast you're going and how tight the curve is, captured by the formula a=v2ra = \frac{v^2}{r}. Plug in your speed and radius, and you've got the answer.

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