A book is lying on the table. What is the angle between the action of the book on the table and the reaction of the table on the book ............ $^o$

A body of mass $60\,kg$ is suspended by means of three strings $P, Q$ and $R$ as shown in the figure is in equilibrium. The tension in the string $P$ is $..........g\,N$

Two masses $M$ and $m$ are connected by a weightless string. They are pulled by a force $F$ on a frictionless horizontal surface. The tension in the string will be

When a body is stationary

In order to test the strength of a rope, one end is tied to a large tree and the other end is  hitched to a team of $2$ horses. The horse pull as hard as they can, but cannot break the  rope. If the rope is untied from the tree and attached to another team of $2$ horses  with equal strength, and the two teams pull in opposite directions, the tension in the rope  will

A chain lying on an absolutely smooth table, half of it hanging over the edge of the table as shown in figure $(a)$. The time it takes to slip off the table is affected if two equal weights be attached, one to each end as shown in figure $(b)$ .
$t_a$ : time taken to slip in situation $'a'$
$t_b$ : time taken to slip in situation $'b'$