A stone tied to the end of a string of 1 m long is whirled in a horizontal circle with a constant speed. If the stone makes 22 revolutions in 44 seconds, what is the magnitude and direction of acceleration of the stone?
- 2 m s-2 and direction along the radius towards the centre
- 2 m s-2 and direction along the radius away from the centre
- 2 m s-2 and direction along the tangent to the circle
- 2/4 m s-2 and direction along the radius towards the centre.
Answer
(1) 2 m s-2 and direction along the radius towards the centre
Solution
Frequency = 2244 = 0.5 s-1
= 2 = 2 0.5 = rad s-1
The speed is constant, there is no tangential acceleration; only centripetal acceleration acts:
a = 2 r = 2 1 = 2 m s-2
As per NCERT, this acceleration is directed along the radius towards the centre.
Answer: (1)