Weight distribution over multiple scales

In summary: So how many forces are acting on the dog?Four, one for each scale supporting the dog.So the equation would be 4x normal force = 180n, and then when one scale is removed it would be 3x normal force = 180n. And to find the normal force on each scale it would be 180n/4 = 45n and 180n/3 = 60n, respectively.In summary, when a dog stands on four scales with each scale reading 45n, the total weight of the dog is 180n and each scale provides a normal force of 45n. When one scale is removed, the total weight remains the same and the remaining scales provide a normal force of
  • #1
Alyssa Jesse
28
0
I am in a first year physics course at university, with little background in maths and science.

Homework Statement



When a dog stands at rest with each of its four feet on a separate set of scales, each scale reads a value of 45n. if this dog then carefully lifts one foot of the a scale and up into the air, what is the reading on each of the remaining three scales? (assume the dogs weight is evenly distributed between the three scales)

Homework Equations



I would add the scales up to 180, assume the dogs weight to be 180n, then divide that by three to get 60n. I have been looking through the textbook and I can't find a relevant way of working this problem out, however I am not sure if it is as simple as it seems.


The Attempt at a Solution



45*4 = 180n/3 = 60n

Any help or confirmation would be greatly appreciated :)
 
Physics news on Phys.org
  • #2
Your solution is correct.

But would you be able to explain WHY it is correct?
 
  • #3
The dogs weight is evenly distributed over all four scales so 4*45n=180n. When one of the scales is removed the dogs weight is now distributed over three scales, so 180/3 = 60n. However, I don't know how to explain this using physics terminology.
 
  • #4
One missing bit is why the total weight is equal to the sum of readings on all the scales. Have you learned of the free body diagram (FBD)?
 
  • #5
No not yet, I saw mention of it in another forum I looked over briefly but don't really understand what its purpose is?
 
  • #6
If you have not been introduced to that, then I think we should not touch that matter just yet.

Do you know that for a body to be in equilibrium the sum of all the forces acting on it must be zero? (This is not the only condition, but it is still a necessary condition.)
 
  • #7
Yes, we have been over that!
 
  • #8
So what forces act on the dog when it's on 4 scales? On 3 scales?
 
  • #9
Gravity and the upward support force/normal force of the floor?
 
  • #10
The dog is supported by the scales, not by the floor. What force does each scale exert on the dog?
 
  • #11
In my textbook it uses the example of standing on scales and says - "Two forces act on the scale. One is...gravity...and the other is the upward support force of the floor"
 
  • #12
Yes, these are the forces that act on the SCALE. But in this case we want to know what forces act on the DOG.

Let's take a simpler example. Say you put an apple on a scale. Since the apple is attracted towards the ground by gravity, yet it is stationary, the scale must clearly provide a force opposite in direction and equal in magnitude to the weight of the apple. And the scale does not just provide the force, it also displays to us the magnitude of the force - that's why we need scales to begin with!
 
  • #13
Thank you! So the two forces acting on the dog are gravity and the support force provided by the scale?
 
  • #14
Not two. There are more than one scales supporting the dog.
 

Related to Weight distribution over multiple scales

1. What is weight distribution over multiple scales?

Weight distribution over multiple scales is a concept used in scientific research to describe the distribution of weight or mass across different scales or levels of organization. This can include microscopic scales such as individual cells, as well as larger scales such as organisms, ecosystems, or even entire planets.

2. Why is weight distribution over multiple scales important?

Understanding weight distribution over multiple scales is important because it can provide insights into the functioning and dynamics of complex systems. By examining how weight is distributed across different scales, we can gain a more comprehensive understanding of how systems operate and how they are affected by various factors.

3. How is weight distribution over multiple scales measured?

Weight distribution over multiple scales can be measured using a variety of techniques, depending on the specific system being studied. For example, in biological systems, scientists may use imaging technologies to visualize the distribution of weight at different scales, while in physical systems, they may use instruments such as scales or balances to measure weight at various levels.

4. What are some factors that can affect weight distribution over multiple scales?

There are many factors that can influence weight distribution over multiple scales. These can include environmental conditions, such as temperature and humidity, as well as internal processes within a system, such as metabolism or growth. Additionally, external factors such as competition or predation can also impact weight distribution in complex systems.

5. How can weight distribution over multiple scales be used in practical applications?

Weight distribution over multiple scales has applications in various fields, such as ecology, medicine, and engineering. For example, understanding how weight is distributed across different scales in an ecosystem can help scientists make predictions about how changes in the environment may affect the overall health and functioning of the system. In medicine, studying weight distribution over multiple scales can help researchers identify potential causes and treatments for diseases that affect different levels of organization in the body. In engineering, this concept can be used to design more efficient and effective structures and systems.

Similar threads

Spacetime Physics (2nd ed.) problem 2-2: Bathroom scale and a Trampoline
    • Introductory Physics Homework Help
Replies
5
Views
935
B Upwards movement -- Lifting weights while standing on a scale
    • Mechanics
Replies
17
Views
1K
What happens if i lift a weight on bathroom scales
    • Introductory Physics Homework Help
Replies
2
Views
993
How Does Weight Distribution Affect the Balance of a Ferris Wheel?
    • Introductory Physics Homework Help
Replies
3
Views
996
Determining mass of a weight on a three spring scale setup
    • Introductory Physics Homework Help
Replies
14
Views
3K
What is the reading on a scale when a chain falls onto it?
    • Introductory Physics Homework Help
Replies
9
Views
1K
Weight of person on Earth, and on a different planet's surface?
    • Introductory Physics Homework Help
Replies
11
Views
2K
How to calculate the uncertainty for weight?
    • Introductory Physics Homework Help
Replies
4
Views
4K
Sled Dogs and Components of Force
    • Introductory Physics Homework Help
Replies
6
Views
2K
B How do mechanical (weighing) scales work?
    • Mechanics
Replies
9
Views
2K

Hot Threads

Recent Insights

Back
Top