A stone of mass $0.3\,kg$ attached to a $1.5\,m$ long string is whirled around in a horizontal circle at a speed of $6\,m s ^{-1}$. The tension in the string is $............\,N$

An aircraft executes a horizontal loop of radius $1.00\; km$ with a steady speed of $900 \;km/h$. Compare its centripetal acceleration with the acceleration due to gravity.

A stone ties to the end of a string $1\,m$ long is whirled in a horizontal circle with a constant speed. If the stone makes $22$ revolution in $44$ seconds, what is the magnitude and direction of acceleration of the stone

A proton of mass $ 1.6  \times 10^{-27} kg$ goes round in a circular orbit of radius $0.10\, m$ under a centripetal force of $4  \times 10^{-13}\, N$. then the frequency of revolution of the proton is about 

An athlete completes one round of a circular track of radius $10\, m$ in $40\, sec$. The distance covered by him in $2 \,min$ $20 \,sec$ is ........ $m$

A particle moves in a circle of radius $5 \;cm$ with constant speed and time period $0.2 \pi\; sec$. The acceleration of the particle is .... $m/sec^2$