The efficiency of a heat engine is given by the expression 
The efficiency of a heat engine is the ratio of the work done by the engine to the heat given as the input to the engine.
The heat engine absorbs Q h from the hot reservoir , performs a work <em>W</em> on the absorbed heat and rejects Qc to the cold reservoir.
Therefore, the work done is given by,
Thus the efficiency is given by,
density = mass/volume. so you need to know the mass and the volume.
When the magnitude of all opposing forces is equal, then the force is called balanced. The forces on W and Y are balanced while the forces on X and Z are unbalanced.
<h2>
Net Force:</h2>
It is defined as the vector sum of all forces acting on the object. The forces with the same magnitude in the opposite direction cancel each other.
<h3>Balanced force: </h3>
When the magnitude of all opposing forces is equal, then the force is called balanced.
<h3>Unbalanced force: </h3>
When a force is more than the opposing force, the force is called unbalanced.
Therefore, the forces on W and Y are balanced while the forces on X and Z are unbalanced.
Learn more about Net Force:
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Answer:
Earth's magnetic field serves to deflect most of the solar wind, whose charged particles would otherwise strip away the ozone layer that protects the Earth from harmful ultraviolet radiation.
