Question

To the end of 80 cm long string is called in a horizontal circle with a constant speed if the stone makes 14 revolutions in 25 second the magnitude of its acceleration is

Answer 1

Length of the string, l = 80 cm = 0.8 m
Number of revolutions = 14
Time taken = 25 s
Frequency, v = Number of revolutions / Time taken  =  14 / 25 Hz
Angular frequency, ω = 2πν
= 2 × (22/7) × (14/25)  =  88 / 25 rad s-1
Centripetal acceleration, ac = ω2r
= (88/25)2 × 0.8
= 9.91 ms-2
The direction of centripetal acceleration is always directed along the string, toward the centre, at all points.