The linear elastic spring with stiffness k and unstretched length ℓu is attached to both t...

The linear elastic spring with stiffness k and unstretched length ℓu is attached to both the vertical wall and the metal block A of mass mA. The metal block B is pushed into A so that the spring compresses a distance d. The block B is then released from rest.

Assuming that friction between the blocks and the surface is non-negligible and that the coefficient of static friction is insufficient to prevent motion, determine the condition on the compression distance d for the blocks to separate. The coefficient of kinetic friction between the blocks and the surface is μk. Hint: The blocks will start to separate when the normal force between them goes to zero.

Figure P3.124