$A$ string of length $L$ fixed at one end carries a mass $m$ at the other end. The string makes $3/\pi$ r.p.s. around the vertical axis through the fixed end. The tension in the string is: (in $mL$)

Two particles of the same mass are moving in circular orbits because of a force given by $F(r) = -\frac{16}{r} - r^3$. The first particle is at a distance $r = 1$,and the second is at $r = 4$. The best estimate for the ratio of kinetic energies of the first and the second particle is closest to:

Two masses $M$ and $m$ are attached to a vertical axis by weightless threads of combined length $l$. They are set in rotational motion in a horizontal plane about this axis with constant angular velocity $\omega$. If the tensions in the threads are the same during motion,the distance of $M$ from the axis is

$A$ man carrying a monkey on his shoulder is cycling smoothly on a circular track of radius $9 \,m$ and completes $120$ revolutions in $3$ minutes. The magnitude of the centripetal acceleration of the monkey is (in $m/s^2$):

One end of a massless spring of spring constant $k$ and natural length $l_{0}$ is fixed,while the other end is connected to a small object of mass $m$ lying on a frictionless table. The spring remains horizontal on the table. If the object is made to rotate at an angular velocity $\omega$ about an axis passing through the fixed end,then the elongation of the spring will be

$A$ particle of mass $m$ is moving in a circular path of radius $r$ in a plane. Its angular momentum is $L$. The value of the centripetal force acting on the particle is: