If $\cos (A-B)=3/5$ and $\tan A \tan B=2$,then which one of the following is true?

The moment of inertia of a body about a given axis is $1.2 ~kg \cdot m^2$. Initially,the body is at rest. In order to produce a rotational kinetic energy of $1500 ~J$,an angular acceleration of $25 ~rad/s^2$ must be applied about the axis for a time duration of: (in $~s$)

What is the time (in $sec$) required for depositing all the silver present in $125 \ mL$ of $1 \ M \ AgNO_3$ solution by passing a current of $241.25 \ A$? $(1 \ F = 96500 \ C)$

$A$ bullet fired into a fixed target loses half of its velocity after penetrating $3 \ cm$. How much further will it penetrate before coming to rest,assuming that it faces constant resistance to motion? (in $cm$)

........ of a reaction cannot be determined experimentally.

The equation of the latus rectum of the parabola ${x^2} + 4x + 2y = 0$ is