Logic would seem to suggest that the sum of the two weights would add up to your total weight, however I just have this niggling suspicion that it might not be so simple (I’m thinking of what happens when you connect resistors in parallel)
My, my, mssmith. No need to get snippy. My college does in fact offer physics. I am already signed up to take the class in the fall. I already took a basic course in high school (a year before most of the other students, as it be).
I just happen to have a really bad memory. Add that to my endless curiousity and you’ve got one big problem.
I’m not being snippy, I’m just poking a little fun at you.
Let me expand on my explanation a little bit.
In any system, the sum of the forces in that system must be zero. Your weight is the force of your body acting on the Earth and is equal to your mass x the acceleration of gravity.
When you are standing, you can be modeled as a structure with two supports held in place by pins (ie no moment around the point of connection. Don’t worry about what that means.) So you have one force pushing downward at your center of gravity. You have 2 forces pushing upward, one at each foot. The sum of the 2 upward forces have to equal the downward force. Thus, the scales will roughtly show half your weight (depending on how you shift your balance).
I am an aerospace engineer, specializing in weights. msmith537 has it right. The sum of the scale readings will always equal your total weight. It doesn’t matter whether you distribute the weight evenly or not. It doesn’t matter how many scales you use (you could weigh a horse using four scales, for example). You just have to be careful to stand still. If you shift your weight between reading the first scale and the second, the total will be off.
Airplanes are weighed using a scale under each wheel truck. For a 747, this means using five scales (747s have two sets of main landing gear). The total of all the scale readings equals the aircraft weight. Also, knowing the weight on each scale and the position of each scale relative to the aircraft will allow you to calculate the center of gravity of the aircraft. This is just as important as knowing the aircraft weight.
In most states, officers in charge of enforcing highway weight restrictions use the same method to spot-check truck weights. A scale is placed in front of each wheel and the truck is driven onto them. The total weight as well as the weight of each axle can then be easily checked.
Another interesting thing to do is to get in a push-up position with your hands on the scale and feet off - see how much of your own body weight you’re actually pressing back up. You are (obviously) not pressing up your full body weight as the occasional person thinks. At the moment I weigh just under 190. Depending on how I position myself, I can put as little as 80lbs pressure on my hands, up to 160lbs (140 for a normal position = about 74% of your weight). Shows you just how much different those wimpy ass-high-in-the-air positions are in terms of cheating.
Yes, in a static system such as the one described the sum of the scales’ display will equal your weight as measured by either of the scales… assuming they are equally accurate.
However, it is not always to achieve a static state. When you shift your weight for balance, the readings will not always add up to the same number. If you bounce up and down on the scales, the sum will swing wildly.
I am 67 and have chronic sciatica. Having tried the doctor, Physio and Osteopath I am now with a chiropractor. The first thing he did was to stand me upright (using a full length mirror with a grid) on 2 sets of scales. The one under my left foot weighed 30 kilos while the other weighed 60 kilos! I asked if I was compensating for the pain down one side but he said that would only account for about 10 pounds not 60. 2 days after the first treatment 8 kilos had been transferred so hopefully it will even up. I did suggest he just reduced the fat side but that wasn’t an option. The cause - could have been an accident but in my case more likely spending 40 years sprawling at a computer screen.
Welcome to the Straight Dope Message Board, mas66670. Please note that the thread you are replying to is over twelve years old. We tend to refer to old threads like this that have been revived as zombies, so don’t be too surprised if you see a lot of zombie jokes as replies.
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Due to the age and nature of this thread I am going to just close it.