Physics

Physics

Problem

A traveller lifts an 8 kg8\,\text{kg} suitcase from the ground and places it on an overhead rack 2.2 m2.2\,\text{m} above the ground while waiting at a railway station. a. (i) Calculate the increase in gravitational potential energy of the suitcase. Take g=9.8 m s−2g = 9.8\,\text{m s}^{-2}. b. (ii) Using g≈10 m s−2g \approx 10\,\text{m s}^{-2} for quick estimation, determine the height to which the same suitcase must be raised so that its potential energy increases by exactly 2500 J2500\,\text{J}.
Intuitive explanation

This is a problem about gravitational potential energy and the work needed to lift an object against gravity. The key insight is that the work you do lifting the suitcase gets stored as potential energy—it depends only on the height change and the object's weight, not on how fast or slow you lift it. Once you know the mass and the vertical distance, you can calculate how much energy the suitcase gains.

Intuitive explanation

This is a problem about gravitational potential energy and the work needed to lift an object against gravity. The key insight is that the work you do lifting the suitcase gets stored as potential energy—it depends only on the height change and the object's weight, not on how fast or slow you lift it. Once you know the mass and the vertical distance, you can calculate how much energy the suitcase gains.

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