Question bank/JEE Main/Physics

A thin uniform rod of mass is hinged at one
end. This rod is maintained in horizontal position by colliding very
tiny balls each of mass m/10 completely elastically 10 times per sec
striking at the opposite end as shown in figure. Find the speed of the
ball - (g = 10 m/sec^2)

Your answerCheck answer

Show answer and solution▾

[IMAGE] Taking torque about hinge:
$MgL/2 = FL$
$mg\frac{L}{2} = 2(\frac{mV}{10})10L$
$V = 2.5m/sec$

Source: Grass-G / P-20 Physcis Paper 12 Dec.docx