A small particle of mass $0.36\mathrm{ }\mathrm{g}$ rest on a horizontal turntable at a distance $25\mathrm{ }\mathrm{c}\mathrm{m}$ from the axis of spindle. The turntable is accelerated at a rate of $\mathrm{\alpha }=1/3\mathrm{ }\mathrm{r}\mathrm{a}\mathrm{d}/{\mathrm{s}}^{-2}$ . The frictional force that the table exerts on the particle $2\mathrm{ }\mathrm{s}$ after the startup is-

What is an artificial satellite? Name any two types of artificial satellite and state their functions.

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, 

An artificial satellite is moving in a circular orbit of radius $36,000 \mathrm{km}$. Calculate its speed if it takes $24$ hours to revolve around the earth.