2. (Free-fall problem) A ball is thrown up in the air. 10 seconds later it reaches the top of its trajectory. What was the original velocity it was thrown upward with?

Explanation:

Using kinematics,

t = 10s

v = 0m/s

a = -9.8m/s^2

Therefore u = v - at = 0 - (-9.8)(10) = 98m/s.

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