Chapter 11, Problem 95CP

The truck shown below is initially at rest with solid cylindrical roll of paper sitting on its bed. If the truck moves forward with a uniform acceleration $a$ , what distance s does it move before the paper rolls off its back end? (Hint: If the roll accelerates forward with $a^{\prime }$ , then is acceleration $a-a^{\prime }$ . Also, $R\alpha =a-a^{\prime }$ .)