Four cubical boxes 1, 2, 3 and 4 - made of the same material - are placed on the ground, and are pushed with a constant force. d1, d2, d3 and d4 are the distances travelled by the boxes. They are related as d3 > d2 > d4 > d1. How are the sides a1, a2, a3 and a4 of the respective boxes related?

Since the boxes are made of same material. A box with more volume will weigh more. More is the weight more is the frictional force. Since frictional force is directly dependent on the weight of the body.

Thus, larger the side of the box more the weight and hence more the frictional force that opposes the applied force.

Since distance travelled by box 3 is highest its weight must be lowest and hence its side is the smallest.

Thus we conclude, the smallest side is a₃ and the largest side is a₁. And the sides of the boxes are related as,

a₃ < a₂ < a₄ < a₁