MCAT Physics Question 19: Answer and Explanation
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Question: 19
4. A 40 kg block is resting at a height of 5 m off the ground. If the block is released and falls to the ground, which of the following is closest to its total mechanical energy at a height of 2 m, assuming negligible air resistance?
- A. 0 J
- B. 400 J
- C. 800 J
- D. 2000 J
Correct Answer: D
Explanation:
Assuming negligible air resistance, conservation of energy states that the total mechanical energy of the block is constant as it falls. At the starting height of 5 m, the block only has potential energy equal to
Because the kinetic energy at this point is 0 J, the total mechanical energy is 2000 J at any point during the block's descent.