Question:-
A mass m attached to a spring is subjected to a harmonic force as shown in figure. The amplitude of the forced motion is observed to be 50mm.
the value of m (in kg) is


Option (A)
0.1
Option (B)
1.0
Option(C)
0.3
Option(D)
0.5
Correct Option:
(A)
Question Solution:
Amplitude (A)=50mm

Mx + Kx = 100 cos (100t) w=100
General solution is x=Acos wt
X = 0 Aw sin wt, x = - Aw2 cost wt

M(-Aw2 cos wt) + K(A cos wt) = 100 cos(wt)

-mAw2 + KA = 100

-m(0.05)(100)2 + 3000(0.05) = 100

-500m + 150 = 100

+m = + 50/500 = 0.1
question-answer-faq-2367