Which action best demonstrates the transformation of mechanical energy to heat energy?
a. digesting a meal
b. burning a candle
c. rubbing hands vigorously
d. melting a piece of ice in sunlight

As air becomes more dense, (select all that apply) o. air weighs less o. gas molecules are closer together o. air is colder o. air weighs more o. gas molecules are further apart o. air is hotter

Precision can be defined as the o exact center of a data set. o reproducibility of a measured value. o correlation between two variables that are measured in a data set agreement between a measured value and an accepted value.

Inside a flashbulb, oxygen surrounds a thin coil of magnesium. when the flashbulb is set off, a chemical reaction takes place in which magnesium combines with oxygen to form magnesium oxide. which of the chemical equations matches the reaction above? a. mg + o2 mgo2 + energy b. 2mg + o mg2o + energy c. 2mg + o2 2mgo + energy d. mg + o mgo + energy