The angular speed of seconds needle in a mechanical watch is

The angular acceleration of a body, moving along the circumference of a circle, is :

The length of second's hand in a watch is $1 \,cm.$ The change in velocity of its tip in $15\, seconds$ is

Two racing cars of masses ${m_1}$ and ${m_2}$ are moving in circles of radii ${r_1}$ and ${r_2}$ respectively. Their speeds are such that each makes a complete circle in the same duration of time $t$. The ratio of the angular speed of the first to the second car is

A car is moving at a speed of $40 \,m / s$ on a circular track of radius $400 \,m$. This speed is increasing at the rate of $3 \,m / s ^2$. The acceleration of car is ....... $m / s ^2$

Two spheres $P$ and $Q$ of equal masses are attached to a string of length $2\,\, m$ as shown in figure. The string and the spheres are then whirled in a horizontal circle about $O$ at a constant rate. What is the value of the ratio
$\left( {\frac{{{\text{Tension in the string between P and Q}}}}{{{\text{Tension in the string between P and O}}}}} \right)?$