Chapter 8, Problem 46AP

Review. As shown in Figure P8.26, a light string that does not stretch changes from horizontal to vertical as it passes over the edge of a table. The string connects m₁, a 3.50-kg block originally at rest on the horizontal table at a height h = 1.20 m above the floor, to m₂, a hanging 1.90-kg block originally a distance d = 0.900 m above the floor. Neither the surface of the table nor its edge exerts a force of kinetic friction. The blocks start to move from rest. The sliding block m₁ is projected horizontally after reaching the edge of the table. The hanging block m₂ stops without bouncing when it strikes the floor. Consider the two blocks plus the Earth as the system. (a) Find the speed at which m₁ leaves the edge of the table. (b) Find the impact speed of m₁ on the floor. (c) What is the shortest length of the string so that it does not go taut while m₁ is in flight? (d) Is the energy of the system when it is released from rest equal to the energy of the system just before m₁ strikes the ground? (e) Why or why not?

Figure P8.26