In a heat transfer problem, U is a function of? temperature and time length and time O width and length temperature and volume

The dimensionless number which replaces the Reynolds number in the case of free convection is the number.

Just part d please

Parts a-c please.

When two objects at different temperatures are brought into contact with one another (such as a hot steel bar dropped into cold water), the cold object will O increase in temperature to the same temperature as the hot object before being placed in the water. O lose as much heat as the hot object loses the cold object will remain unchanged O gain as much heat as the hot object loses

Variation of Thermal Conductivity. A flat plane of thickness Ax has one surface maintained at T and the other at T. If the thermal conductivity varies according to temperature as k = A + bT + cT³ where a, b, and c are constants, derive an expression for the one-dimensional heat flux q/A.

radiation

A large slab of aluminum has a thickness of 10 cm and is initially uniform in temperatureat 400◦C. It is then suddenly exposed to a convection environment at 90◦Cwith h=1400 W/m2 · ◦C. How long does it take the center to cool to 180◦C?

Q: water at 200² flows over 90.3m square Plate at velocity of 6 m/s at constant Plate is maintained Temperature at 556° calclate the heat by the plate. heat Transfer