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 

Two cars $S_1$ and $S_2$ are moving in coplanar concentric circular tracks in the opposite sense with the periods of revolution $3 \,min$ and $24 \,min$, respectively. At time $t=0$, the cars are farthest apart. Then, the two cars will be 

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

A fly wheel is accelerated uniformly from rest and rotates through $5 \,rad$ in the first second. The angle rotated by the fly wheel in the next second, will be.........$rad$

If speed of a particle moving in a circle of radius $2\,m$ is given as $v = 2t + 2$, then its centripetal acceleration after $1\, s$ will be   ......... $m/s^2$

An electric fan has blades of length $30 \,cm$ as measured from the axis of rotation. If the fan is rotating at $1200\,$ r.p.m. , the acceleration of a point on the tip of the blade is about ..........  $m/sec^2$