Question:
A small block B is placed on another block A of mass $5 \mathrm{~kg}$ and length $20 \mathrm{~cm}$. Initially the block B is near the right end of block A. A constant horizontal force of $10 \mathrm{~N}$ is applied to the block A. All the surfaces are assumed frictionless. Find the time elapsed before the block $B$ separates from $A$.
Solution:
