Question

a 75 kg physics student rides in the elevator. find the apparent weight of the student if:
a. the elevator is moving vertically up at constant velocity of 5.0 J m/s

b. the elevator decelerates as it moves up at 3.5m/s^2

Answer 1

case a) since the elevator is moving with constant velocity, then it is an inertial reference system, so the weight is given by the same formula, namely:
P=m*g=...?

Answer 2

case b), on our student is acting fictitious force, due to the acceleration of the elevator. Here is the situation:

so we can write this vector equation:
\[{{\mathbf{W}}_{{\mathbf{APPARENT}}}} = M{\mathbf{g}} - M{\mathbf{a}}\]
from which we have the subsequent scalar equation:
\[\left| {{{\mathbf{W}}_{{\mathbf{APPARENT}}}}} \right| = Mg + Ma\]
for the magnitude of the apparent weight