13. A 10 kilogram rock is dropped off the top of a 20 meter tall building. What is the kineticenergy of the rock right before it impacts the ground?

Aprisoner is forced to go into one of three rooms, but he can choose which room. the first room is ablaze with fire. the second one is rigged with explosives that will go off as soon as he enters. the third contains a pair of lions who haven't eaten in years. which room should he choose to survive?

Coal contains energy. a. light b. kinetic c. chemical d. mechanical

Five structural isomers have the formula c6h14. where needed, draw the structure and give the iupac name of all five isomers.