Four particles given, have same momentum which has maximum kinetic energy

A block of mass $m$ is sliding on a fixed frictionless concave surface of radius $R$. It is released from rest at point $P$ which is at a height of $H \ll R$ from the lowest point $Q .$

$(a)$ What is the potential energy as a function of $\theta$, taking the lowest point $Q$ as the reference level for potential energy?

$(b)$ What is the kinetic energy as a function of $\theta$ ?

$(c)$ What is the time takes for the particle to reach from point $P$ to the lowest point $Q$ ?

$(d)$ How much force is exerted by the block on the concave surface at the point $Q$ ?

Write the definition of work and kinetic energy.

Two solids $A$ and $B$ of mass $1\, kg$ and $2\, kg$ respectively are moving with equal linear momentum. The ratio of their kinetic energies $(K.E.)_{ A }:( K.E. )_{ B }$ will be $\frac{ A }{1},$ so the value of $A$ will be ….. .

A bomb of mass $9\,kg$ explodes into $2$ pieces of mass $3\,kg$ and $6\,kg.$ The velocity of mass $3\,kg$ is $1.6\, m/s$, the K.E. of mass $6\,kg$ is ………… $J$