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

Options

A. `650 cm//s^(2)`
B. `680 cm//s^(2)`
C. `750 cm//s^(2)`
D. `990 cm//s^(2)`

Answer

d

Explanation

If angular velocity is `omega` and radius of circular path is r then, acceleration `alpha=omega^(2)r`
`T=("Number of revolution")/("Time taken")=25/14=1.78s`
and `omega=(2pi)/1.78=3.52 rad//s`
Hence, `alpha=(3.52)^(2)xx80=991.23~~990cm//s^(2)`