Concept:According to the Law of Conservation of Energy, the loss in gravitational potential energy equals the gain in kinetic energy for a freely falling body.
Formula:$$ \text{Loss in P.E} = \text{Gain in K.E} = mg\Delta h $$
Solution:- Mass (\( m \)) = 6.0 kg
- Distance fallen (\( \Delta h \)) = 60 m (Note: we use the distance it has fallen, not its height from the ground).
- Using \( g \approx 9.8 \text{ m/s}^2 \):
- \( K.E = 6.0 \times 9.8 \times 60 = 58.8 \times 60 = 3528 \text{ J} \)
- This is approximately 3500 J.
Why other options are incorrect:Using the remaining height of 20m instead of the fallen distance gives \( 6 \times 9.8 \times 20 \approx 1200 \text{ J} \) (Option C). Using the total height 80m gives \( \approx 4800 \text{ J} \) (Option A).
Quality & Fidelity Assurance:
Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.