Introduction:
In this question, we are given the specifications of a shunt motor and we need to explain the concept of mechanical loss in detail. Let's break down the answer into the following headings:

What is a Shunt Motor?
A shunt motor is a type of DC motor where the field winding is connected in parallel (shunt) with the armature winding. It operates on the principle of Lorentz force, where the interaction of the armature current and magnetic field produces a rotational motion.

Working Principle:
When a DC voltage is applied to the motor, current flows through the armature winding and the field winding. The armature winding carries the load current, while the field winding provides the necessary magnetic field for the motor to operate.

Armature Resistance:
The armature resistance in the motor is given as 0.1 ohm. This resistance causes a voltage drop across it, which leads to power loss in the form of heat. The power loss due to armature resistance can be calculated using the formula: P_loss = I^2 * R, where I is the armature current and R is the armature resistance.

Shunt Field Resistance:
The shunt field resistance in the motor is given as 200 ohm. Similarly, this resistance also causes a voltage drop and power loss. However, the power loss in the shunt field resistance is relatively small compared to the armature resistance.

Output Power:
The motor delivers an output power of 9.4 kW. This power is the mechanical power developed by the motor, which is the power transferred to the load. It is calculated using the formula: P_out = V * I, where V is the applied voltage and I is the armature current.

Mechanical Loss:
Mechanical loss refers to the power loss that occurs within the motor due to various factors. These losses are mainly categorized into two types: friction and windage losses.

Friction Loss:
Friction loss occurs due to the rubbing or sliding contact between various moving parts of the motor, such as bearings, brushes, and gears. This friction leads to power loss in the form of heat. Friction losses can be reduced by using high-quality bearings and lubrication.

Windage Loss:
Windage loss occurs due to the resistance offered by the surrounding air to the rotating parts of the motor. As the motor rotates, it displaces the air, which requires energy. This energy loss is known as windage loss. Windage losses can be reduced by streamlining the motor design and minimizing air resistance.

Total Mechanical Loss:
The total mechanical loss in the motor is the sum of friction loss and windage loss. It is calculated by subtracting the output power from the input power. In this case, the mechanical loss can be calculated as: P_loss = P_in - P_out, where P_in is the input power supplied to the motor.

Conclusion:
In conclusion, a shunt motor experiences mechanical loss due to various factors such as armature resistance, friction loss, and windage loss. These losses lead to a decrease in the overall efficiency of the motor. To improve the efficiency, it is important to minimize these losses through proper maintenance, lubrication, and design optimization.