Three boxes, X, Y and Z are on a horizontal conveyor belt. The conveyor belt has an effective mass of 20 kg and each of the box X, Y and Z has a mass of 15 kg.
With the three boxes stationary with respect to the belt, the system consisting of the belt and the three boxes move together at a constant speed of 2.1 m s–1. There is a driving force of 90 N which remains constant with time acting on the belt.
The resistive force on the “belt-boxes system” by the rollers is equal to the total mass of the system.
The distance between adjacent boxes is 6.3 m. When each box reaches the right end, the box will be lifted off vertically as shown in Figure 2a.
Figure 2a
Figure 2b shows the belt-boxes system before box X reaches the right end where it will be lifted.
Figure 2b
Draw a free-body diagram of the forces on the belt-boxes system in Figure 2b. Include any significant values in the diagram.