Work Done In Thermodynamics

Coefficient of performance of refrigerator is




Now, if is heat extracted and is work performed them,

where, heat extracted from of water make it ice

So,

The frictional force between the block and the plank is given by:

where:

• is the coefficient of friction,
• is the mass of the block,
• is the acceleration due to gravity.

For the block to remain in equilibrium on the plank, the frictional force must equal the force required to accelerate the block with the plank. Let the maximum horizontal acceleration of the plank be .

The force required to accelerate the block is:

The frictional force provides the maximum force that can be applied without the block slipping. Hence, the maximum acceleration of the plank is:

Simplifying:

Thus, the correct answer is Option (1), with the maximum horizontal acceleration being .

The forces and are acting at angles to the horizontal surface. We need to find the reaction force exerted by the surface.

The horizontal components of the forces and do not affect the vertical reaction of the surface because they do not contribute to the vertical force.

The vertical components of the forces and are responsible for the reaction from the surface. The vertical component of each force is given by:

The total vertical force acting on the body is the sum of the vertical components of the forces and :

The body is in equilibrium, so the reaction force from the surface must balance the total vertical force, which would typically be downward.

However, because the surface is smooth and the body is not moving vertically, the net reaction from the surface in the vertical direction is zero due to the exact cancellation of forces acting on the body.

Thus, the reaction force is zero.

Step 1: Work done in stretching a spring
The work done in stretching a spring from an initial extension to a final extension is given by: Given: - Spring constant, N/m,
- Initial extension, cm = m,
- Final extension, cm = m.
Step 2: Calculating the work done
Substituting the values: Step 3: Conclusion
Thus, the work required to stretch the spring further by another 10 cm is: