sphere

A sphere of radius 5 mm is initially in equilibrium at 400 °C in a furnace. It is suddenly removed from the furnace and dipped in a well-stirred water bath at 20 °C, with a convect...

The value of the surface integral ∬_S z dx dy where S is the external surface of the sphere x² + y² + z² = R² is

Aluminium is casted in a cube-shaped mold having dimensions as 20 mm × 20 mm × 20 mm. Another mold of the same mold material is used to cast a sphere of aluminium having a diameter...

The surface integral $\iint_S \mathbf{F} \cdot \mathbf{n}\,dS$ over the surface $S$ of the sphere $x^2 + y^2 + z^2 = 9$, where $\mathbf{F}=(x+y)\mathbf{i}+(x+z)\mathbf{j}+(y+z)\mat...

A small copper ball of $$5$$ $$mm$$ diameter at $$500$$ $$K$$ is dropped into an oil bath whose temperature is $$300$$ $$K.$$ the thermal conductivity of copper is $$400$$ $$W/m.$$...

With a solidification factor of $$0.97 \times {10^6}s/{m^2},$$ the solidification time (in seconds) for a spherical casting of $$200$$ $$mm$$ diameter is