Experimental Determination of “g” using an Elevator

Click For Summary

Homework Help Overview

The discussion revolves around an experimental approach to determine the acceleration due to gravity (g) using an elevator. Participants are exploring how the acceleration of the elevator relates to gravitational strength while measuring kinematic values during the elevator's motion.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • Participants are questioning how the acceleration of the elevator can provide information about g, with some suggesting that additional measurements like mass or normal force might be necessary. Others propose measuring the acceleration that results in zero apparent weight on a scale, while also considering the implications of conducting the experiment in different gravitational environments, such as the Moon.

Discussion Status

The discussion is active, with participants expressing uncertainty about the feasibility of the proposed method. Some have offered ideas about measuring kinematic variables, while others are questioning the assumptions underlying the experiment. There is no explicit consensus, but various interpretations and approaches are being explored.

Contextual Notes

Participants note that the experiment involves measuring acceleration, velocity, distance, and time, but express concerns about the relevance of these measurements to determining g, especially in different gravitational contexts. There is also a mention of using LoggerPro and its capabilities, which may influence the experimental setup.

The Head
Messages
137
Reaction score
2
Homework Statement
Experimentally determine the value of ‘g’ by measuring the displacement, velocity, time, and acceleration of an object (using LoggerPro) in an elevator.
Relevant Equations
g=(ma - Fn)/m

d=vi*t + 1/2at^2
I’m kind of stuck on this one. I don’t see how we can use the acceleration of an elevator to find anything about the value of g. We can of course get the acceleration of the elevator, but it feels like that would be independent of gravitational strength. I feel like we need the mass or the Normal Force, but those aren’t things we’re asked to measure. We are just measuring kinematical values in an elevator climbing or falling several stories. Help!
 
Physics news on Phys.org
Hmm. The only thing that comes to mind is measure the acceleration downward in the elevator that results in zero force on the scale measuring your weight in the elevator...
 
berkeman said:
Hmm. The only thing that comes to mind is measure the acceleration downward in the elevator that results in zero force on the scale measuring your weight in the elevator...
Thanks for your reply— it seems like it is missing something to me too! Apparently the instructor says it can be done by continuously monitoring a, v, d, and t in the elevator. But to me, if you did this experiment on the Moon, all four of those variables could be the same as the values you get on Earth! So from that logic, it seems like whatever we measure has nothing to do with “g.”
 
The Head said:
Thanks for your reply— it seems like it is missing something to me too! Apparently the instructor says it can be done by continuously monitoring a, v, d, and t in the elevator. But to me, if you did this experiment on the Moon, all four of those variables could be the same as the values you get on Earth! So from that logic, it seems like whatever we measure has nothing to do with “g.”

With the elevator at rest you could drop an object from known height ##d## that takes ##t## to hit the floor, and get ##g = \frac{2d}{t^2}##.
 
Um... What exactly does LoggerPro let you measure? What sensors have you got? If it measures the apparent weight of an object you would seem to not need the elevator, just a standard mass.
 

Similar threads

  • · Replies 22 ·
Replies
22
Views
2K
  • · Replies 20 ·
Replies
20
Views
2K
  • · Replies 30 ·
2
Replies
30
Views
4K
  • · Replies 33 ·
2
Replies
33
Views
8K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 11 ·
Replies
11
Views
4K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 13 ·
Replies
13
Views
4K
  • · Replies 9 ·
Replies
9
Views
3K
  • · Replies 15 ·
Replies
15
Views
4K