Multiple choice general knowledge science & technology

If a rock is thrown straight up with an initial velocity of 30 meters per second, the rock will reach a height of approximately ...

  1. 90 m

  2. 45 m

  3. 30 m

  4. 60 m
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

At maximum height, the rock's final velocity is zero. Using the kinematic equation v² = u² + 2as where v = 0, u = 30 m/s, and a = -9.8 m/s² (downward), we solve for height: 0 = 30² + 2(-9.8)h, giving h = 900/19.6 ≈ 45.9 meters, which rounds to approximately 45 meters.

Keep practicing — related questions