Time period for the force F1=T1 Time period for the force F2=T2 If both forces acts simultaneously then the resultant force is F, F=F1+F2 Let, time period for the force F be T Now, F=F1+F2 ‌mω2y=mω12y+mω22y‌‌(∵F=mω2y) ‌ω2=ω12+ω22 ‌⇒‌‌(‌