- Aand
- Band
- Cand
- Dand
View written solutionFree
Correct answer: A
-
Given data
The particle hits the rod at distance
The rod is pivoted at one end and rotates freely about that pivot.
-
Moment of inertia of the rod about the pivot
For a uniform rod about one end,
-
Use conservation of angular momentum about the pivot
During collision, external impulse at pivot has zero moment about the pivot, so angular momentum about pivot is conserved.
Initial angular momentum of the small mass:
After collision, the particle returns back along the same path, so its final velocity is opposite in direction. Taking initial direction as positive,
Hence final angular momentum of particle is
Rod's angular momentum after collision:
Therefore,
-
Use conservation of kinetic energy
Collision is elastic, so total kinetic energy is conserved.
Initial KE:
Final KE:
So,
-
Solve equations
From (1):
Now test the options.
Option A: m/s
This matches the stated .
Check energy:
So Option A is correct.
Option B: gives , not rad/s. Incorrect.
Option C: gives
not rad/s. Incorrect.
Option D: gives
close to , but now check energy:
which is not equal to J. So incorrect.
-
Final answer
The correct option is:
-
Comparison with stored correct answer
Stored correct answer: A
My derived answer also: A
Hence, they agree.
More from Rotational Motion
- Two point-like objects of masses and are fixed at the two ends of a rigid massless rod of length . This system is suspended vertically from a rigid ceiling using a thin wire attached to… Includes diagram2023 · Numerical
- An annular disk of mass , inner radius and outer radius is placed on a horizontal surface with coefficient of friction , as shown in the figure. At some time, an impulse is applied at a height above the… Includes diagram2023 · Multiple correct
- A thin circular coin of mass and radius is initially in a horizontal -plane. The coin is tossed vertically up ( direction) by applying an impulse of … Includes diagram2023 · Numerical
- At time , a disk of radius starts to roll without slipping on a horizontal plane with an angular acceleration of . A small stone is stuck to the disk. At , it is…2022 · Numerical
- A solid sphere of mass and radius rolls without slipping on a fixed inclined plane with an angle of inclination from the horizontal. Two forces of magnitude each,… Includes diagram2022 · Numerical
- List I describes four systems, each with two particles and in relative motion as shown in figures. List II gives possible magnitudes of their relative velocities (in ) at time . Which one of the… Includes table Includes diagram2022 · MCQ
- A flat surface of a thin uniform disk of radius is glued to a horizontal table. Another thin uniform disk of mass and with the same radius rolls without slipping on the circumference of , as shown in the figure. A… Includes diagram2022 · MCQ
- A horizontal force F is applied at the center of mass of a cylindrical object of mass m and radius R, perpendicular to its axis as shown in the figure. The coefficient of friction between the object and the ground is . The center of… Includes diagram2021 · Multiple correct