2-18. A pulley system with two crates are released from rest. Crate A has a mass and crate B has a mass . The coefficient of kinetic friction between crate A and the inclined surface follows a normal distribution . When , find the distribution of velocity at .

Solution:

Crate A

where

Impulse

Crate B

Combining the two equations above, we have

Solving for the final velocity mean

Therefore, . Ans.