How Does Configuration Affect Frictional Forces on Identical Blocks?

[StephenDoty]

The blocks shown have equal mass and are made of the same material,and the velocity is the same in each figure. The total frictional force on the blocks are

A. Greater in C than in A or B
B. The same in C and A
C. The same in A,B, C
D. The same in A and B
E. The same in C and B.

Isnt the fictional force the same for all B and C since the only difference between them is that in B the two masses are on top of one another and being pulled be a string, and in C the two masses are beside each other and attached to the same string, which is being pulled?

 

[Doc Al]

Isnt the fictional force the same for all B and C since the only difference between them is that in B the two masses are on top of one another and being pulled be a string, and in C the two masses are beside each other and attached to the same string, which is being pulled?

Right.