During an arm wrestling match, participants put their arms on the table and wrestle with their palms. If the force exerted by the players are equal, where is the balanced force acting?

 Compare the magnitudes of centripetal and centrifugal force.

Two similar trucks are moving with the same velocity on a road. One of them is loaded while the other is empty. Which of the two will require a larger force to stop it?

A car of mass $200 \mathrm{kg}$ is revolving in a circular track of radius $70 \mathrm{m}$ with angular velocity $0.2 \mathrm{rad} {\mathrm{s}}^{-1}$, then find the centripetal force in Newton.

A small block of mass $100 \mathrm{g}$ is tied to a spring of spring constant $7.5 \mathrm{N} {\mathrm{m}}^{-1}$ and length $20 \mathrm{cm}.$ The other end of spring is fixed at a particular point $A.$ If the block moves in a circular path on a smooth horizontal surface with constant angular velocity $5 \mathrm{rad} {\mathrm{s}}^{-1}$about point $A,$ then tension in the spring is

Two stones of masses $m$ and $2m$ are whirled in horizontal circles, the heavier one in radius $\frac{r}{2}$ and the lighter one in radius $r$. The tangential speed of lighter stone is $n$ times that of the tangential speed of the heavier stone. They are reported to experience the same centripetal force. The value of $n$ is, 

Give an example of non-contact force.