Thursday, October 25, 2018

soft question - Should these be called "weights" or "masses"?




Picture of small metal disks slotted onto as hook, such as could be attached to a spring to study Hooke's law


Yeah, those circular metal disks. Weights or masses? I call them weights because when I attach them to a spring I'm interested in their weight, but it feels odd saying a "Pick up the 100g weight". "Pick up the weight with a mass of 100g sounds better" but it still feels wrong.


I don't like to call them masses, because I've never heard anyone else call them masses, unless it's someone trying to correct me for making the 'mistake'.



Answer



It is absolutely fine to call these objects "weights", since you are interested in their weight - i.e. the force of gravity on them. You are not using them for their inertial properties.


Dictionary definition of weight: (Dictionary.com - definition 5)



a body of determinate mass, as of metal, for using on a balance or scale in weighing objects, substances, etc.



NB - this definition makes it explicit that a weight has mass. In other words - while you call it a weight (the object), the physical property is mass (100 gram). Which, at a particular point on earth, translates into a weight.



No comments:

Post a Comment

classical mechanics - Moment of a force about a given axis (Torque) - Scalar or vectorial?

I am studying Statics and saw that: The moment of a force about a given axis (or Torque) is defined by the equation: $M_X = (\vec r \times \...