Four identical blocks are moving on a surface for which the coefficient of kinetic friction between each block and the surface is µ_k. The velocity of each block is indicated by the vector on the block. For which block is the force of friction between the surface and the block greatest? A) 1 B) 2 C) 3 D) 4 E) The force of friction is the same for all blocks.

Question

Quizplus · Accepted Answer

Since all four blocks have the same coefficient of kinetic friction with the surface, the force of friction will depend only on the normal force acting on each block (which is equal to its weight since the blocks are not accelerating in the vertical direction). Since all four blocks have the same weight and are moving on the same surface, they will experience the same normal force and therefore the same force of friction. Therefore, the answer is E, the force of friction is the same for all blocks.

Four Identical Blocks Are Moving on a Surface for Which