B Vector of forces (question about how a scale works)

[noosah]

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?

 

[Mark44]

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.

 

[A.T.]

the force that the object act on the scale, is this what the scale reads?

Yes.

 

[sophiecentaur]

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.

 

[Chestermiller]

Let's see your free body diagram of the scale.