GATE Mechanical Engineering (ME) 2018 Shift 1 Solved Paper

The equation of motion for a spring-mass system excited by a harmonic force is $\mathit{M}.=\mathit{F}\cos \left(\mathit{\omega }\mathit{t}\right)$ Where $\mathit{M}$ is the mass, $\mathit{K}$ is the spring stiffness, $\mathit{F}$ is the force amplitude and $\mathit{\omega }$ is the angular frequency of excitation. Resonance occurs when $\mathit{\omega }$ is equal to.