Question

On a rough inclined plane. The force between two blocks is zero if:

• mu_1 > mu_2
• mu_1 < mu_2
• mu_1=mu_2 Solution

The only possible way there is force between the two is if the m_2 is moving slowly than m_1.

We assume that they start from rest, so they have same initial velocity, so everything comes down to just acceleration since v=u+at

The acceleration of any block on the inclined plane is given by a = gsintheta-mugcostheta

So the relation would be gsintheta-mu\1gcostheta<=gsintheta-mu\2gcostheta

=>m_2<=m_1

So A, C