# College Physics

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A 1.70 kg object attached to a spring moves without friction and is driven by an external force given by F = (3.00 N) sin(2πt).

(a) If the force constant of the spring is 20.0 N/m, determine the period.

_____s For this one I tried 2*pi*sqrt(1.7/20) but it said my answer differed from the correct answer by more than 10%.

(b) If the force constant of the spring is 20.0 N/m, determine the amplitude of the motion.
_____cm For this one I tried -kx = 3 sin(2πt) --> x = (-3/k) sin 2πt ---> Amplitude = 3/k = 3/20 = 0.15 m = 15 cm but it said I was off by 100%.

Any help would be appreciated!

• College Physics -

Frequency will be the driving frequency
ω = 2π (s^-1),
T = 2•π/ ω = 1 s.
Amplitude
A = (F/m)/(ω^2 - ω(o)^2)=
=(F/m)/(ω^2 - k/m)=
= (3/1.7)/(4•π ^2 - 20/1.7) = 0.064 m.

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