Two blocks `A` and `B` of masses `1 kg` and `3 kg` are attached with two massless strings as shown in figure. The system is kept over a smooth table and it is rotates about the axis shown in figure with constant angular speed `omega=2 rad//s`. Find direction and magnitude of centrifugal force on
(a) A as observed by `B`
(b) `B` as observed by `A`

Answer

A, B, C, D

Explanation

(a) Acceleration of `B` ,
`a_(B)=r_(B)omega^(2)=(2)(2)^(2)=8m//s^(2)`
Mass of `A` `m_(A)=1Kg` .
`:.` Centrifugal force (or pseudo force) on `A` ,
`F_(A)m_(A)a_(B)=(1)(8)=8N`
Direction of this force is in the opposite direction of `a_(B)` . Therefore, direction of `F_(A)` is radially outwards.
(b) Acceleration of `A` , `a_(A)=r_(A)omega^(2)=(1)(2)^(2)=4m//s^(2)`
Mass of `B` , `m_(B)=3Kg`
`:.` Centrifugal force on `B` ,
`F_(B)=m_(B)a_(A)=(3)(4)=12N`
Direction of `F_(B)` is also radially outwards.