Which of the following alkaline earth metals shows anomalous behavior and has an electronegativity similar to that of aluminum?

$A$ particle is moving on a circular path of radius $r$ with uniform speed $v$. The change in velocity when the particle moves from $P$ to $Q$ is $(\angle POQ = 40^\circ)$.

$A$ wheel having a moment of inertia $2 \, kg \cdot m^{2}$ about its vertical axis rotates at the rate of $60 \, rpm$ about this axis. The torque which can stop the wheel's rotation in one minute would be:

$A$ body projected vertically upwards crosses a point twice in its journey at a height $h$ just after $t_1$ and $t_2$ seconds. Maximum height reached by the body is

Which of these is not an important component of initiation of parturition in humans?

For a Poisson variate $X$, if $P(X=2)=3 P(X=3)$, then the mean of $X$ is :