lever scale
Học thuậtThân thiện
Definition
Noun: A lever scale is a portable weighing device. It operates using a simple machine called a lever, which is a pivoted bar with arms of unequal length. The object to be weighed is placed on one arm, and a known counterweight or sliding weight is adjusted on the other arm until balance is achieved, indicating the object's weight.
Usage
A lever scale is used for measuring the weight of objects, typically in settings where portability is important, such as in markets, kitchens, or for personal use. It functions based on the principle of mechanical equilibrium.
Examples
- The vendor used a lever scale to weigh the fresh vegetables at the market.
- Before the trip, he checked his luggage on a small lever scale to avoid airline fees.
- Traditional lever scales are still common in some regions because they do not require electricity.
Advanced Usage
- Historical Context: The design of the lever scale is ancient, based on the earliest principles of mechanics and balance. It represents a fundamental application of physics in everyday tools.
- Mechanical Principle: The operation is governed by the law of the lever, where . In a lever scale, the force is the weight of the object and the counterweight.
Variants and Related Words
- Balance Scale: A more general term for any device that measures mass by balancing two forces. A lever scale is a specific type of balance scale.
- Steelyard: A specific, common type of lever scale where the object is hung from the short arm and a counterweight slides along a calibrated longer arm.
- Portable Scale: A descriptive term highlighting the key feature of a lever scale.
Synonyms
- Balance
- Steelyard
- Weighing scale
Antonyms
- (Conceptual) Spring scale (a device that measures weight by the extension of a spring, not by balancing levers).
Related Phrases
- To tip the scales: An idiom meaning to give a slight advantage to one side in a competition or decision, derived from the image of a scale barely moving out of balance.
- Her excellent presentation tipped the scales in her favor for the promotion.
Noun
- a portable balance consisting of a pivoted bar with arms of unequal length