Ball A is thrown vertically upward from the top of a 30-m-high-building with an initial velocity of 5 m/s. At the same instant, Another ball B is thrown upward from the ground with an initial velocity of 20 m/s. Third ball C is thrown upward from the ground with initial velocity 21.49 m/s after 1 second.
(A) Determine the time when all three balls will cross each other.
(B) Determine the height at which all three balls will cross each other.