Wile E Was at the Top of a Cliff When He

Short Answer

Wile E. was at the top of a cliff when he spotted Road Runner at the bottom of the cliff. Wile E. jumped off the cliff, using an umbrella as a parachute to get a steady speed. After 2 minutes, Wile E. was 960 feet from the bottom of the cliff, and after 5 minutes, he was 480 feet from the bottom.
A) What was Wile E.'s speed going down?
B) What was the height of the cliff, top to bottom?
C) When did Wile E. reach the bottom of the cliff?