Final answer:
The heavier the load applied to a motor, the more it will experience slip due to a decrease in back emf and an increase in current flow. Overheating can occur if the motor runs too slowly under heavy load. Friction also affects efficiency and the required coefficient of static friction on inclined surfaces.
Step-by-step explanation:
The relationship between motor load and slip in an operating motor is a fundamental concept in physics. When a mechanical load increases, such as when an electric wheelchair ascends a hill, the motor slows and experiences more slip. The increased load causes a drop in back electromotive force (emf), which leads to a higher current flow, allowing the motor to do more work.
Consequently, this can also lead to a risk of overheating due to the resistive power in the coil, described by the formula P = I² R. However, if the motor is running without a mechanical load, it will reach a point where its angular velocity balances out the emfs, only using energy necessary to overcome internal friction. Friction itself plays a significant role in efficiency and work output, exemplified by the equation Wout = Win - W₁, where Wout represents the work output after accounting for frictional losses.
Efficiency can be improved by lubrication, which reduces the friction between surfaces in contact. A higher coefficient of static friction is needed on steeper inclines to prevent slipping, further illustrating the critical role of friction in mechanical systems. Overall, the heavier the load, the greater the amount of slip experienced by an operating motor.