Which of the following groups of forces could be in equibrium
$3\, N, 4\, N, 5 \,N$
$4\,N, 5 \,N, 10 \,N$
$30\,N, 40 \,N, 80 \,N$
$1\,N, 3\, N, 5\, N$
Three weights $W, 2W$ and $3W$ are connected to identical springs suspended from a rigid horizontal rod. The assembly of the rod and the weights fall freely. The positions of the weights from the rod are such that
A smooth cylinder of mass $m$ and radius $R$ is resting on two corner edges $A$ and $B$ as shown in fig. The relation between normal reaction at the edges $A$ and $B$ is
A boy is hanging from branch of a tree as shown. Angle between his arm, for tension to be maximum in arms must be ............ $^o$