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

Two stones of masses $m$ and $3m$ are whirled in horizontal circles,the heavier one in a radius of $(r/3)$ and the lighter one in a radius of $r$. The tangential speed of the lighter stone is $n$ times that of the heavier stone when they experience the same centripetal force. The value of $n$ is:

$A$ $500 \,kg$ car takes a round turn of radius $50 \,m$ with a velocity of $36 \,km/h$. The centripetal force is (in $\,N$)

$A$ particle describes a horizontal circle in a conical funnel whose inner surface is smooth with a speed of $0.5 \, m/s$. What is the height of the plane of the circle from the vertex of the funnel in $cm$?

$A$ child of mass $5\,kg$ is going round a merry-go-round that makes $1$ rotation in $3.14\,s$. The radius of the merry-go-round is $2\,m$. The centrifugal force on the child will be $.......\,N$.

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