A circular disc with a groove along its diameter is placed horizontally on a rough surface. A block of mass 1 kg is placed as shown. The co-efficient of friction between the block and all surfaces of groove and horizontal surface in contact is `mu=2/5`. The disc has an acceleration of `25m//s^2` towards left. Find the acceleration of the block with respect to disc. Given `cos theta=4/5`, `sin theta=3/5`.

Answer

A, B

Explanation

Applying pseudo force `ma` and resolving it.
Applying `F_(n et)=ma_r`
`ma cos theta-(f_1+f_2)=ma_r`
`macostheta-muN_1-muN_2=ma_r`
`ma cos theta - mu ma sin theta - mu mg =ma_r`
`implies a_r=acostheta-muasintheta-mug`
`=25xx4/5-2/5xx25xx3/5-2/5xx10=10m//s^2`