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## Homework Statement

A mass of 240 g oscillates on a horizontal frictionless surface at a frequency of 3.0 Hz and with amplitude of 4.5 cm.

a) What is the effective spring constant for this motion?

b) How much energy is involved in this motion

m = 240 g = 0.24 kg

A = 4.5 cm = 0.045 m

f = 3.0 Hz

g = 9.8 m/s^2

## Homework Equations

k= F/x = mg/x

E = K + U

K = 1/2*m*v^2

U = 1/2*k*x^2

v = ±ε√(A^2-x^2)

ε = 2πf = √(k/m)

v=0 when x=±A since the object stops briefly before travelling back towards the equilibrium.

^^^ That means K=0

## The Attempt at a Solution

a) k= F/x = mg/x = [(0.240 kg)(9.8 m/s^2)]/(0.045 m) ≈ 52.27 N/m

b) E = 1/2*(52.27 N/m)(.045m)^2 = 0.053 J

^^^ Does this all look correct?