Answer :
Final answer:
Monica's scale underestimates her weight since the actual weight is 122 lbs but the scale reads 99.82 lbs. Bathroom scales measure weight but are usually calibrated to display mass, however, the calibration assumes Earth's gravitational pull, which means readings differ in environments with different gravity like the Moon. Therefore correct option is C
Explanation:
If Monica's actual weight is 122 lbs and her scale shows a reading of 99.82 lbs, then it can be said that her scale underestimates her weight. Bathroom scales are designed to measure weight, which is the force of gravity acting on an object. The springs inside a scale compress proportionally to the weight applied on them and provide this measurement.
Scales, especially digital ones, are calibrated to give readings in mass units such as kilograms, despite measuring the force in newtons or pounds. Typically, the weight in newtons is divided by the acceleration due to gravity (approximately 9.80 m/s2) to estimate the mass.
It's essential to distinguish the difference between mass and weight; mass is a measure of how much matter an object contains, while weight is the measure of the force exerted by gravity on that mass. Consequently, the same scale would not display the same mass on the Moon as on Earth due to the difference in gravitational pull. Additionally, the reliability of a scale's reading can be influenced by external forces, such as pushing on a table while standing on the scale.
