Question

A ball of weight 200 grams, is tied to the end of a cord and whirled in a horizontal circle of radius 0.6 m. If the ball makes five complete revolutions in 2 seconds, what will be the linear speed of the ball?
A. 3.2 m/s
B. 4.6 m/s
C. 5.6 m/s
D. 6.6 m/s
E. 9.42 m/s

Answer 1

Linear speed = Distance / Time

Distance = 5 × 2 × pi × r

= 5 × 2 × 22/7 × 0.6

= 132 / 7

= 18.85 m

speed = 18.85 / 2

= 9.42 m/s



Thanks

Answer 2

Answer : Linear speed of the ball is 9.42 m/s.

Explanation :

Weight of the ball, m = 200 g = 0.2 Kg

Radius of the circle, r = 0.6 m

Time taken, t = 2 s

Distance covered in 5 complete revolutions is, $d=2\pi r\times 5=10\ \pi r$

We know that $s=\dfrac{d}{t}$

$s=\dfrac{10\ \pi r}{t}$

$s=\dfrac{10\times 3.14\times 0.6\ m}{2\ s}$

$s=9.42\ m/s$

So, the linear speed of the ball is 9.42 m/s.

Hence, the correct option is (E).