Question

Centripetal acceleration is

• A. a constant vector
• B. a constant scalar
• C. a magnitude changing vector
• D. not a constant vector

Answer 1

Answer: (D)

Centripetal acceleration, $a_c=\frac{v^2}{R}$ where $v$ is the speed of an object and $R$ is the radius of the circle. It is always directed towards the centre of the circle. Since $v$ and $R$ are constants for a given uniform circular motion, therefore the magnitude of centripetal acceleration is also constant. However, the direction of centripetal acceleration changes continuously. Therefore, a centripetal acceleration is not a constant vector.