A large boulder is ejected vertically upward from a volcano with an initial speed of 40.7 m/s. Air resistance may be ignored.
1) At what time after being ejected is the boulder moving at a speed 19.8 m/s upward?
2) At what time is it moving at a speed 19.8m/s downward?
3) When is the displacement of the boulder from its initial position zero?
4) When is the velocity of the boulder zero?
5) What is the magnitude of the acceleration while the boulder is moving?
6) What is the direction of the acceleration while the boulder is moving?