A mass of $2 \,kg$ is whirled in a horizontal circle by means of a string at an initial speed of $5$ revolutions per minute. Keeping the radius constant the tension in the string is doubled. The new speed is nearly ....... $rpm$
$14 $
$10$
$2.25$
$7$
The maximum velocity (in $ms^{-1}$) with which a car driver must traverse a flat curve of radius $150 \,m$ and coefficient of friction $0.6$ to avoid skidding is
If the radius of curvature of the path of two particles of same masses are in the ratio $1 : 2$, then in order to have constant centripetal force, their velocity, should be in the ratio of
A block of mass $m$ is kept on horizontal turn table at $x$ distance from the centre. If coefficient of friction between block and surface of turn table is $\mu$, then maximum angular speed of the table so that block does not slip
A block of $200\, g$ mass moves with a uniform speed in a horizontal circular groove, with vertical side walls of radius $20\, cm$. If the block takes $40\, s$ to complete one round, the normal force by the side walls of the groove is
A car is moving on a horizontal circular track of radius $0.2 \,km$ with a constant speed. If coefficient of friction between tyres of car and road is $0.45$, then speed of car may be ........ $m / s$ [Take $g=10 \,m / s ^2$ ]