Friction Understanding at Molecular Level

Q. Two blocks $A$ and $B$ of masses $m_A$ and $m_B$ have velocity $v$ and $2v$, respectively, at a a given instant. A horizontal force $F$ acts on the block $A$. There is no friction between ground and block $B$ and coefficient of friction between $A$ and $B$ is $\mu$. The friction

1. on $A,$ supports its motion.
2. on $B,$ opposes its motion relative to $A$.
3. on $B,$ opposes its motion.
4. opposes the motion of both.

Q. Two blocks $A$ and $B$ of masses $m_A$ and $m_B$ have velocity $v$ and $2v$, respectively, at a a given instant. A horizontal force $F$ acts on the block $A$. There is no friction between ground and block $B$ and coefficient of friction between $A$ and $B$ is $\mu$. The friction

1. on $A,$ supports its motion.
2. on $B,$ opposes its motion relative to $A$.
3. on $B,$ opposes its motion.
4. opposes the motion of both.

Q. If two surfaces are polished highly smooth, the friction between them increases.

1. True
2. False