Finding gravitational potential energy

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SUMMARY

The gravitational potential energy (GPE) of an elevator stopping at the eighth floor, relative to the sixth floor, is calculated using the formula E = mgh. Given the mass of the elevator and its contents as 1350 kg and the height difference between the sixth and eighth floors as 12 meters, the correct calculation yields a GPE of 158,760 J, which rounds to approximately 1.5 x 105 J, confirming the textbook answer. The initial miscalculation arose from incorrectly using the total height of 30 meters instead of the 12-meter difference.

PREREQUISITES
  • Understanding of gravitational potential energy (GPE) formula: E = mgh
  • Basic knowledge of physics concepts such as mass, height, and gravitational acceleration
  • Familiarity with unit conversions and scientific notation
  • Ability to interpret and apply physics equations in problem-solving scenarios
NEXT STEPS
  • Review the concept of gravitational potential energy in different contexts
  • Learn about the implications of height differences in energy calculations
  • Explore the relationship between work and energy in physics
  • Practice similar problems involving GPE with varying mass and height scenarios
USEFUL FOR

Students studying physics, particularly those focusing on mechanics and energy concepts, as well as educators looking for practical examples of gravitational potential energy calculations.

jaron
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Homework Statement


The distance between the sixth and the eleventh floors of a building is 30.0m. The combined mass of the elevator and its contents is 1350 kg.

a) find the gravitational potential energy of the elevator when it stops at the eighth floor, relative to the sixth floor.

(the answer in the back of my textbook is : 1.5x10^5 J )

Homework Equations


now i am thinking E=mgh, but i am also thinking that i an going to need to do something about the work formula. i know that w=F"d, and when the force is acting in the opposite direction, you must use W=F"d cos 180'. but this might be totally irrelevant.


The Attempt at a Solution


with this equation i am getting: E=1350(9.81)(30) E=397305 J
 
Physics news on Phys.org
The distance between the 6th and 11th is 30 meters.

The distance between the 6th and 8th then is 12 meters isn't it?
 
yeah, thanks. i feel like an idiot about the question now..
forgot to consider that fact that the 30m was for the whole height and not for floor 6-8.
 

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