Un casquillo de cobre de 8 kilogramos tiene que calentarse de 25 a 140 grados Celsius con el fin de expandirlo pata que se ajuste sobre un eje. ¿Cuanto calor se requirió?

354200J

Explanation:

Given parameters:

Mass of copper bushing = 8kg

Initial temperature  = 25°C

Final temperature  = 140°C

Unknown:

Quantity of heat required to heat this mass = ?

Solution:

The amount of heat required to heat mass from one temperature to another is given by;

                  H = m c Δt

where m is the mass

          c  is the specific heat

        Δt is the change in temperature

C is a constant and for copper, its value is 385J/kg°C

 Input the parameters;

            H = 8 x 385 x (140 - 25) = 354200J

what experimental evidence led scientists to change from the previous model to this one?

a few of the positive particles aimed at a gold foil seemed to bounce back.

the colors of light emitted from heated atoms had very specific energies.

experiments with water vapor showed that elements combine in specific proportions.

cathode rays were bent in the same way whenever a magnet was brought near them.