Question

Sarah stands on a bathroom scale inside an elevator. Sarah's mass is 50 kg. What does the scale read in Newton if the elevator moves upward with constant velocity of 1.5 m/s.? What does the scale read if the elevator moves upward for a short period of time with the acceleration of 2 m/s2? draw a free body diagram and show your work. (20 points) (g=9.8 m/s2 )

Please draw the diagram!

Answer 1

Here we have given that,

Sarah's mass M = 50 kg.

a) so here the scale reading when the elevator moves upward with constant velocity of 1.5 m/s then

Due to this constant velocity acceleration will be zero

So that from the free body diagramwe have the relation as,

R - mg = 0

R = 50 × 9.8 = 490 N

Hence

The reading of the scale will be 490 N

b) now the scale reading if the elevator moves upward for a short period of time with the acceleration of 2 m/s2

Here we have acceleration so that,

R - mg = ma

R = m(a+g) = 590 N

Which is the reading of the scale.

free body diagram :-