The work done by a body against friction always results in

Options

A. loss of kinetic energy
B. loss of potential energy
C. gain of kinetic energy
D. gain of potential energy

Explanation

To solve the question, "The work done by a body against friction always results in," we can follow these steps:

### Step 1: Understand the Concept of Work Done Against Friction
When a body moves against friction, it has to exert a force to overcome the frictional force. The work done (W) can be defined as the product of the force (F) applied and the distance (d) moved in the direction of the force.

### Step 2: Analyze the Effect of Friction
Friction opposes the motion of the body. Therefore, when work is done against friction, it means that energy is being used to overcome this opposing force.

### Step 3: Relate Work Done to Energy Transformation
The work done against friction is not lost; rather, it is transformed into another form of energy. In this case, the energy is transformed into thermal energy (heat) due to the friction between the surfaces in contact.

### Step 4: Conclusion
Since the work done against friction results in the conversion of kinetic energy into thermal energy, we can conclude that the work done by a body against friction always results in a loss of kinetic energy.

### Final Answer
The work done by a body against friction always results in a loss of kinetic energy.

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