# How much do you weight in an elevator?

by WRNWRN
Tags: elevator, weight
 P: 2 Does your weight change in elevator? I have recently found an answer to this question but I can't understand it completely. So, here is the answer : No, your weight is unchanged. To provide the acceleration upwards, the floor or scale must exert on your feet an upward force that is greater in magnitude than your weight. It is this greater force that you fell, which you interpret as feeling heavier. The scale reads this upward force, not your weight, and so its reading increases. I can't understand how the force exerted by the floor on one's feet acts on the scale.
 P: 418 Weight is the force acting upon an object due to the acceleration of gravity. Going up or down in an elevator does not change the acceleration of gravity of therefore your weight does not change. However your apparant weight will change.
 P: 145 If you are having trouble visualising this, imagine someone is underneath you and the weighing scale, and they are pushing the scale up towards your feet. So it will read a higher weight because it's being pressed upwards against your feet. Also, you and the scale are lifted off the ground. That imaginary person is the floor of the elevator. (If you need to understand how a bathroom weighing scale works, squeeze it in your hands) Edit: Note that Einstein's elevator says you can't tell the difference between gravity and an equal strength acceleration, so think about what 'weight' means.
 P: 298 How much do you weight in an elevator? we always made the distinction between mass and weight: http://en.wikipedia.org/wiki/Mass_versus_weight Mass does not change when acceleration acts upon it, weight does. This is why you can be 'weightless' when the elevator moves down with an acceleration equal to g, but you cannot become massless.
 P: 126 It really depends on your definition of weight. Weight is the force needed to support mass in a gravitational field. But GR tells us that a gravitational field and accelerated motion are equivalent, so the force exerted on a mass by acceleration should also be considered weight. Therefore, your weight does increase in an elevator accelerating in a direction opposite the gravitational field.
 Mentor P: 15,203 alexg is exactly right. The answer depends on what one means by "weight". Some texts define it as mass times gravitational acceleration, others as what an ideal spring scale measures.
Mentor
P: 12,013
 Quote by daqddyo1 Bigfooted and Alex, I have several concerns about your explanations a) Weight is the DOWNWARD force exerted by gravity on a mass. It is never an upward force. b) Weight never changes unless the mass changes or the FORCE of gravity on the mass changes.
From wikipedia: http://en.wikipedia.org/wiki/Weight

 In contrast to this "purely gravitational" definition, some books use an "operational" definition,[citation needed] defining the weight of an object as the force measured by the operation of weighing it (using a force-sensitive scale, such as a spring scale), in vacuum. This is the force an object exerts on a scale, and is equal to the force required to support it (although in the opposite direction to the "weight" force). This force measured by force-scales is the same as what some other sources term the object's "apparent weight".
By your definition you would still have weight while in orbit. I think both views are correct, and you need to account for both when applicable.
 P: 124 This might help... the term "acceleration due to gravity" is not really that easy to define. It's kind of relative. http://en.wikipedia.org/wiki/Proper_acceleration http://en.wikipedia.org/wiki/Force_of_gravity http://en.wikipedia.org/wiki/Earth%27s_gravity http://en.wikipedia.org/wiki/Weightlessness http://en.wikipedia.org/wiki/Gravita...ral_relativity OCR
P: 126
 Quote by daqddyo1 Bigfooted and Alex, I have several concerns about your explanations a) Weight is the DOWNWARD force exerted by gravity on a mass. It is never an upward force. .
No, weight is the upward force preventing an object from moving downward in a gravitational or accelerated field.

 b) Weight never changes unless the mass changes or the FORCE of gravity on the mass changes.
Or the acceleration changes.

 Related Discussions Introductory Physics Homework 2 Introductory Physics Homework 1 Introductory Physics Homework 10 Introductory Physics Homework 3 Introductory Physics Homework 6