A disc of radius R and mass M is rolling horizontally without slipping with speed ν. It then moves up an inclined smooth surface as shown in figure. The maximum height that the disc can go up the incline is :
(A)gv2
(B)43gv2
(C)21gv2✓ Correct
(D)32gv2
Answer: (C)
Solution
On the frictionless incline no torque acts on the disc about its own centre, so its angular velocity — and with it the rotational kinetic energy 21Iω2 — stays fixed all the way up. Only the translational kinetic energy is available to convert into gravitational potential energy: 21mv2=mgh. Solving for the maximum height, h=2gv2.
JEE Main · 2024 · 01 Feb 2024 · Shift 2 · Single correct option