When you hold a pen and write on your notebook, what kind of force is exerted

$1$. by you on the pen?

$2$. by the pen on the notebook?

$3$. by you on the notebook?

Suppose the magnitude of the nuclear force between two protons varies with the distance between them, as shown in the figure. Estimate the ratio of nuclear force/Coulomb force for $x=8 \mathrm{fm}$. (b) $x=4\mathrm{fm}$, (c) $x=2\mathrm{fm}$ and (d) $x=1\mathrm{fm}\left(1\mathrm{fm}={10}^{-15} \mathrm{m}\right)$.

List all the forces acting on block $B$, as shown in the following figure.

List all the forces acting (a) on pulley $A$. (b) the boy and (c) the block $C$ in figure.

Figure shows a boy pulling a wagon on the road. List as many forces as you can which are relevant to this figure. Find the pairs of forces connected by Newton's third law of motion.

Figure shows a cart. Complete the table shown below.