What is the gravitational field intensity at any point inside a uniform spherical shell?

The gravitational intensity at the centre $O$ of a hemispherical shell of uniform mass density has the direction indicated by which arrow?

If the value of gravitational intensity at a point is $0.7\, N/kg$,what will be the magnitude of the gravitational force acting on an object of mass $5\, kg$ at that point (in $, N$)?

$A$ thin rod of length $L$ is bent in the form of a circle. Its mass is $M$. What force will act on a mass $m$ placed at the centre of this circle? $(G = \text{universal gravitational constant})$

What is the intensity of the gravitational field at the center of a spherical shell?

There are two bodies of masses $100 \, kg$ and $10000 \, kg$ separated by a distance of $1 \, m$. At what distance from the smaller body will the intensity of the gravitational field be zero?