(a) A bathroom scale has a spring that is compressed by 1.50 cm when a 165 kg person stands on the scale. Assuming the spring is described by Hooke's law, find its force constant.

(b) How much would it be compressed if a 94.0 kg person stands on the scale in an elevator that is accelerating upward at 1.25 m/s2?

1 answer

(a)
F=k•Δx
F=mg =>
mg=k•Δx
k= mg/Δx =165/0.015 = 11000 N/m
(b)
m₁a=N-m₁g
N=m₁(g+a)
k•Δx₁= m₁(g+a)
Δx₁=m₁(g+a)/k=
=94(9.8+1.25)/11000=0.094 m