Question

A brass ball is tied to a thin wire and swung so as to move uniformly in a horizontal circle. Which of the following statements in this regard is / are true?
1. The ball moves with constant velocity
2. The ball moves with constant speed
3. The ball moves with constant acceleration
4. The magnitude of the acceleration of the ball is constant
Select the correct answer using the code given below:

• A. 1 only
• B. 1 and 3
• C. 1, 2 and 4
• D. 2 and 4 only

Answer 1

The correct option is D 2 and 4 only

since the direction of the movement changes in such motion , it can't have constant velocity. but velocity's mag. does not change , so speed remains same.

$\overrightarrow{a}=-\frac{v^2}{r^2}\overrightarrow{r}$

hence a changes but magnitude is same.

D is correct