Vector of forces (question about how a scale works)

Click For Summary
SUMMARY

The discussion centers on the mechanics of how a scale measures weight, specifically through the interaction of forces. When an object exerts a downward force due to its weight, the scale applies an upward normal force that counters this weight, reaching equilibrium. The reading on the scale corresponds to the force exerted by the object, which is the weight force, provided the scale is not accelerating. The mechanism typically involves a spring or strain gauge that translates the force into a readable measurement.

PREREQUISITES
  • Understanding of Newton's Third Law of Motion
  • Basic knowledge of force equilibrium
  • Familiarity with scale mechanisms, such as springs and strain gauges
  • Ability to interpret free body diagrams
NEXT STEPS
  • Study the principles of force equilibrium in static systems
  • Learn about different types of scales, including mechanical and electronic scales
  • Explore the design and function of strain gauges in measuring force
  • Review examples of free body diagrams and their applications in physics
USEFUL FOR

Physics students, engineers, and anyone interested in understanding the principles of force measurement and scale operation.

noosah
Messages
1
Reaction score
0
so my question is a little dumb, if an object on a scale has a weight that points downwards and the scale exert normal force on the object upwards cancelling the forces acted on the object then what does the scale read? also the action-reaction pair to the normal force is supposed to be the force that the object act on the scale, is this what the scale reads?
 
Physics news on Phys.org
noosah said:
so my question is a little dumb, if an object on a scale has a weight that points downwards and the scale exert normal force on the object upwards cancelling the forces acted on the object then what does the scale read? also the action-reaction pair to the normal force is supposed to be the force that the object act on the scale, is this what the scale reads?
The spring on the scale (assuming that that's how the scale is built -- other technologies such as strain gauges can also be used) is depressed by the object on the scale (the downward action force), and reaches equilibrium when the reactive force of the compressed spring (the reaction force) counters the downward force of the object. The distance that the spring is compressed is linked to a pointer on the scale's dial that moves a corresponding distance.
 
  • Like
Likes   Reactions: vanhees71
noosah said:
the force that the object act on the scale, is this what the scale reads?
Yes.
 
noosah said:
is this what the scale reads?
If the scale is not actually accelerating up or downwards then the scale measures the weight force of the object on it.
 
  • Like
Likes   Reactions: vanhees71
Let's see your free body diagram of the scale.
 
  • Like
Likes   Reactions: vanhees71

Similar threads

  • · Replies 9 ·
Replies
9
Views
3K
  • · Replies 31 ·
2
Replies
31
Views
2K
  • · Replies 5 ·
Replies
5
Views
3K
  • · Replies 11 ·
Replies
11
Views
4K
  • · Replies 10 ·
Replies
10
Views
726
  • · Replies 35 ·
2
Replies
35
Views
4K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 15 ·
Replies
15
Views
2K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 9 ·
Replies
9
Views
5K