Question

A turn table is rotating about the fixed vertical axis. A particle of mass $m$ is lying on a table at rest with respect to the table. An observer is standing over a block of mass $M$ moving with an acceleration $a$. Find the magnitude of pseudo-force on a particle of mass $m$ as observed by the observer. (Given a body is subjected to an acceleration called centripetal acceleration directed towards the centre when it is rotating and is equal to $r{\omega }^2$ )

• A. $m(a-r{\omega }^2)$
• B. $Ma$
• C. $m(a+r{\omega }^2)$
• D. $ma$

Answer 1

The correct option is D $ma$

Using the concept of pseudo force in the frame of observer standing over the block, we have
acceleartion of the body of mass $m$ is $a$
$\therefore$ Pseudo force ${\overrightarrow{F}}_s=m_{\text{body}}{\overrightarrow{a}}_{\text{frame of reference}}=-ma\hat{i}$
Hence magnitude, $F_s=ma$