The discussion revolves around a physics problem involving an object in an elevator, where the scale reads a higher weight than the object's actual weight. Participants are exploring the implications of this scenario on the acceleration of the elevator and the forces at play.
There is active engagement with various interpretations of the forces and the readings on the scale. Some participants suggest that the scale measures force while being marked in units of mass, leading to further questioning about the accuracy of the free body diagram and the forces exerted by the elevator.
Participants are navigating assumptions about the scale's measurements and the forces acting in the elevator system. There is a focus on understanding the relationship between mass, weight, and the readings provided by the scale in a non-standard context.
Quincy said:Homework Statement
An object weighs 65 kg. When it is in an elevator on a bathroom scale, the scale reads 82 kg. What is the acceleration of the elevator and what is its direction?
Homework Equations
FG = mg
The Attempt at a Solution
(82 kg)(9.8) = 803.6 N
803.6 N = (65 kg)(a)
a = 12.36
12.36 - 9.8 = 2.6 m/s2 upwards
What are the scales that the object is sitting on actually measuring?Quincy said:Also, what would the free body diagram look like? Would there be a normal force upwards, and the gravitational force & the force from elevator pointing downwards?
They are measuring mass. I was also surprised by this since one would think they'd be measuring weight/Newtons... Anyways, is the free body diagram correct?heth said:What are the scales that the object is sitting on actually measuring?
Quincy said:They are measuring mass. I was also surprised by this since one would think they'd be measuring weight/Newtons... Anyways, is the free body diagram correct?
Quincy said:Also, what would the free body diagram look like? Would there be a normal force upwards, and the gravitational force & the force from elevator pointing downwards?
LowlyPion said:There is the N force up and the m*(g + a) down.
The Scale is measuring force, but as nothing in life is ever so simple it's marked in units of mass weight, which is the way I think most people interact with mass.
Quincy said:The normal force is upwards, the gravitational force is downwards, and (m)(a) is downwards? By (m)(a), do you mean the force of the elevator? Or is there no force from the elevator?