Question

A particle moves along a semi circular path of radius $r$ in time $t$ with constant speed, then its

• A. average speed is $\frac{\pi r}{2t}$
• B. average velocity is $\frac{r}{t}$
• C. displacement is $2\pi r$
• D. distance travelled is $2r$
• E. average acceleration is $\frac{2\pi r}{t^{2}}$

Hint:

Logic Tip: A common mistake is assuming average acceleration is zero because "speed is constant." Acceleration measures the change in the velocity *vector*. A complete $180^{\circ}$ turn creates the maximum possible velocity change ($2v$) for a given speed.

Answer 1

Answer: (E)