Mass Weight Definition Quantity of matter in object Force exerted by gravity on object Instrument used Balance Spring balance or dynamometer Unit g or kg Newton (N) Changes with position No yes Mass Weight Definition Quantity of matter in object Force exerted by gravity on object Instrument used Balance Spring balance or dynamometer Unit g or kg Newton (N) Changes with position No yes Mass Weight Definition Quantity of matter in object Force exerted by gravity on object Instrument used Balance Spring balance or dynamometer Unit g or kg Newton (N) Changes with position No yes Mass Weight Definition Quantity of matter in object Force exerted by gravity on object Instrument used Balance Spring balance or dynamometer Unit g or kg Newton (N) Changes with position No yes