a 75kg person is standing on a scale in an elevator. what is the reading of the scale in newtons if the elevator (a) is at rest, and (b) moving up with a constant velocity of 2.0 m/s?
kg’s (kilograms) are a unit of mass. Newtons are a unit of force, which is what a scale measures
FORCE = MASS x ACCELERATION.
In both A) and B) parts of your question, acceleration is equal to the force of gravity which is 9.807 meters/sec. Therefore the answer to both A) and B) is:
Force = 75kg x 9.807 meters/second^2
Force = 735.525 kg-meters/second^2
Final Answer: Force = 735.525 newtons