A ball is thrown vertically upward from the ground with an initial speed of 12 m/s. What is the maximum height reached by the ball? (Ignore air resistance and take g = 10 m/s².)
Show the answer and explanation
Correct answer
A. 7.2 m
Principle or equation
For vertical motion under constant acceleration, the maximum height is reached when the velocity becomes zero. Using the kinematic equation v² = u² + 2as, where v = 0, u = 12 m/s, a = -10 m/s², and s is the displacement.
Why this answer is correct
At maximum height, the final velocity v = 0. Using v² = u² + 2as, 0 = (12)² + 2(-10)s => 0 = 144 - 20s => s = 144/20 = 7.2 m. Therefore, the maximum height is 7.2 m.
Example
If a ball is thrown upward with 20 m/s, the maximum height is (20²)/(2*10) = 20 m.
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