Most Important Selected Qs for JEE AdvancedPhysicsWork, Power and Energy
Paragraph The cross-section of a fixed cylinder (not allowed to rotate and translate) with horizontal axis is as shown. One end of a light inelastic string is fixed at top of cylinder of radius R and a small block of mass m is tied to the other end of string. Initially the block is at rest with the portion of string not in contact with cylinder being vertical and having length L as shown. At the lowest position the b
Options
- A2 R
- B5 R
- C3 R
- D2 R 3
Correct answer
A. 2 R
Step-by-step solution
Since u = 2 gL , the highest point to which the block shall reach is u ^2 2 ~g = L distance above its initial position. Hence at highest point, the thread has rotated by 3 =60^ and the block is at same horizontal level as centre of cylinder as shown. gathered x= R 30 =2 R T=m g 60^ = m g 2 gathered tangential acceleration a_t = g 60^ = 3 ~g 2