A stone tied to the end of a string 80 cm long is whirled in a horizontal circle with a constant speed. If the stone makes 14 revolutions in 25 s, the magnitude of acceleration is :

Options

A. `20 ms^(-2)`
B. `12 m//s^(-2)`
C. `9.9 ms^(-2)`
D. `8 ms^(-2)`

Answer

C

Explanation

`omega=(14xx2pi)/25`
`:.` magnitude of acceleration
`=omega^(2)r=((14xx2pi)/25)^(2)xx80/100=9.9 m//s^(2)`