posted by Sabrina on .
an 800 N person stands on a scale in an elevator. What is his apparent weight when the elevator is accelerating upward at 2 m/s^2? B) what5 is his apparent weight when the elevator is acc. downward at 2m/s^2? c) what is his apparent weight when the elevator is moving downward at a constant velocity of 2m/s^2?
Try setting up a force balance on the person. "The apparent weight" W is the force that would act upward from a measuring scale or the floor, and the true weight M g acts downwards.
According to Newton's second law,
W - M g = M a, is a is measured postive upwards.
All three parts of the problem can be solved with this equation. a = +2 m/s^2 in (a), -2 m/s^2 in (b) and 0 in (c). Solve for W in each case.