A merry - go - round , made of a ring - like platfrom of radius R and Mass M , is revolving with angular speed ` omega` .A person of mass M is standin
A merry - go - round , made of a ring - like platfrom of radius R and Mass M , is revolving with angular speed ` omega` .A person of mass M is standing on it ,At one instant , the person jumps off the round , radially aways from the centre of the round (as seen from the round ). the speed of the round of afterwards is
A. `2 omega`
B. `omega`
C. `(omega)/(2)`
D. 0
1 Answers
Correct Answer - a
As no external torque acts on the system , angular momentum should be conserved .
Hence `I omega`= constant …(i)
where ,I is moment of inertia of the system and `omega` is angular velocity of the system .
From Eq.(I) `I_(1)omega_(1)=I_(2)omega_(2)`
( where `omega_(1) and omega_(2)` are angular velocities before and after jumping )
`implies I omega=(I)/(2)xxomega_(2)`
(as mass reduced to half hence moment of inertia also reduced to half )
`implies omega_(2)= 2omega`