The angle between vector $$\vec{Q}$$ and the resultant of $$(2 \vec{Q}+2 \vec{P})$$ and $$(2 \vec{Q}-2 \vec{P})$$ is :

A wooden block of mass $$5 \mathrm{~kg}$$ rests on a soft horizontal floor. When an iron cylinder of mass $$25 \mathrm{~kg}$$ is placed on the top of the block, the floor yields and the block and the cylinder together go down with an acceleration of $$0.1 \mathrm{~ms}^{-2}$$. The action force of the system on the floor is equal to :

The electric field between the two parallel plates of a capacitor of $$1.5 \mu \mathrm{F}$$ capacitance drops to one third of its initial value in $$6.6 \mu \mathrm{s}$$ when the plates are connected by a thin wire. The resistance of this wire is ________ $$\Omega$$. (Given, $$\log 3=1.1$$)