Answer:
B) 225 m/s^2
Explanation:
The rock hits the ground at 15m/s and travels 50cm=0.5m through the ground until it stops.
The acceleration is supposed to be uniform, so the formula we have to use is , which for acceleration is:
Taking the <em>downwards direction as positive</em> (the direction of traveling, so the initial velocity and displacement will be positive), substituting our values for that movement we have:
Where the <em>negative sign indicates that it is pointing upwards.</em>
The answer to your question is D solid