Most Important Selected Qs for JEE AdvancedPhysicsRotational Motion
A thin uniform rod of length 2 , mass m is bent and pivoted at A and connected to massless string as shown in figure whole system is in vertical plane. Now string is cut. Choose the correct options.
Options
- AMaximum K.E. of system is mg 4 (1+ 10 )
- BTension in string CD before cut is 3 mg 4
- CMoment of inertia about hing (A) is m ^2
- DAngle made by AB, with vertical is ⁻¹ ( 1 3 ) where system has maximum K.E.
Correct answer
D. Angle made by AB, with vertical is ⁻¹ ( 1 3 ) where system has maximum K.E.
Step-by-step solution
AO = ( 3 l 4 )^2+ ( l 4 )^2 aligned & = 4 10 & k E _ max = mg 4 (1+ 10 ) & I_n= ( m 2 ^2 3 )+ ( m 2 ( ^2 12 ) )+ m 2 ( ( 5 2 )^2 ) & = m ^2 2 ( 1 3 + 1 12 + 5 4 ) & = m ^2 2 ( 4+1+3 5 12 )= 5 6 ~m ^2 aligned For tension before cutting Torque _n=0 mg ( 3 l 4 )=T(l) T= 3 4 m g