What's the most reliable source of energy on earth?

What is the kinetic energy of a 10-kg bicycle moving at 10 m/s

In 1995 a research group led by eric cornell and carl wiemann at the university of colorado successfully cooled rubidium atoms to the 20-200 nk temperature range. assuming (incorrectly) that the rubidium atoms behave liké particles of a classical ideal gas, calculate the rms speed of a rubidium atom at a temperature of 112.0 nk. in the experiments one particular isotope of rubidium was used, rubidium-87. the molar mass of this isotope is 86.91 q/mol. tries 0/20 submit answer

The specific heat of silver is 0.057 calories/gram°c. if 10.0 grams of silver were heated and the temperature of the sample changed by 20.0°c, how many calories of heat energy were absorbed by the sample?