The measure of angle in degrees through which a pendulum swings if its length is 45 cm and its tip describes an arc of length 11 cm.

Options

A. `20^(@)`
B. `18^(@)`
C. `16^(@)`
D. `14^(@)`

Answer

D

Explanation

Here, `r = 45 cm ` and `l = 11 cm`.
`:.` Let the angle be `theta^(c )`, then.,
`theta = (l)/(r ) = ((11)/(45))^( c)`
Now, `pi^(c ) = 180^(@)`
`rArr ((11)/(45))^(c ) = (180/pi xx 11/45)^(@)`
`= (180 xx 7/22 xx 11/45)^(@) = 14^(@)`.