2-3. Each of the two blocks has a mass . The coefficient of kinetic friction on all surfaces of contact is . If a horizontal force  moves the bottom block, Determine acceleration of block  for the following cases:

(1)  are constants.

(2)  is a constant  while . Assume  are independent.

(1) When  are constants.

Case 1

Block A:

Ans.

Case 2

Block B:

Block A:

Since

Solving the above equations yields

Ans.

(2) When

Case 1:

Ans.

Ans.

Thus,  is normally distributed with  and .

Case 2:

Ans.

Ans.

Thus,  is normally distributed with  and .