Please could someone help me out?!

Which material burns faster? metal aluminum

Athe top of a hill, an athlete on a skateboard has x joules of mechanical energy. how much mechanical energy will she have at the bottom of the hill? ignore the effects of friction.

Asuspension of yeast cells is being grown under anaerobic conditions such that glucose is degraded to ethanol and carbon dioxide. if one wishes to follow this process by monitoring the release of 14co2, at which positions in the glucose molecule would the 14c label need to be incorporated?