Energy Sizing of a Belt Conveyor Motor: A Work Energy and Power Approach with a Horizontal and an Inclined Section

This working paper documents a worked engineering example presented in a guest (“mirror”) class on work, energy and power for first-year physics students. A belt conveyor moves 25 kg boxes at a constant speed of 2.0 m/s along a horizontal section followed by an inclined section. Using only the definition of mechanical work, the work–energy theorem and the definition of power, the paper determines the force, the work and the power that the motor must supply in each section. The most demanding section is the incline, which requires about 308.7 W of design power. After applying a correction factor of 1.5 to all candidate motors, only the 0.75 HP and 1.0 HP options remain adequate, and the 0.75 HP motor is the smallest suitable choice. A follow-up scenario with 30 kg boxes raises the design power to about 370.4 W and shows that the 0.75 HP motor is then only marginally sufficient. The example illustrates how an exact physical calculation avoids both oversizing and undersizing, and how friction coefficients link maintenance and energy efficiency.