Castel left the science museum and traveled toward the mountains. Sumalee left one hour later traveling 10 km/h faster in an effort to catch up to him. After two hours Sumalee finally caught up. What was Castel's average speed? Show your work.

Why does lightning travel from clouds to the ground? a. the negatively charged ground attracts the positive charge from the clouds b. charges are exchanged between negatively charged clouds and positively charged ground c. gravity pulls the negatively charged energy from clouds downward d. gravity pulls the positively charged energy from clouds downward