Concepts Of Physics MCQ Edition [Volume 1]PhysicsSimple Harmonic Motion
Initially, all the springs displayed in the figure are unstretched when a man begins pulling the block. The man applies a constant force F to the block. Determine the amplitude and the frequency of the block's motion.
Options
- AAmplitude: F(k₂ + k₃) k₁ k₂ + k₂ k₃ + k₃ k₁ , Frequency: 1 2 M(k₂ + k₃) k₁ k₂ + k₂ k₃ + k₃ k₁
- BAmplitude: F(k₁ + k₂) k₁ k₂ + k₂ k₃ + k₃ k₁ , Frequency: 1 2 k₁ k₂ + k₂ k₃ + k₃ k₁ M(k₁ + k₂)
- CAmplitude: F(k₂ + k₃) k₁ k₂ + k₂ k₃ + k₃ k₁ , Frequency: 1 2 k₁ k₂ + k₂ k₃ + k₃ k₁ M(k₂ + k₃)
- DAmplitude: F k₁ + k₂ + k₃ , Frequency: 1 2 k₁ + k₂ + k₃ M
Correct answer
C. Amplitude: F(k₂ + k₃) k₁ k₂ + k₂ k₃ + k₃ k₁ , Frequency: 1 2 k₁ k₂ + k₂ k₃ + k₃ k₁ M(k₂ + k₃)
Step-by-step solution
The springs k₂ and k₃ are connected in series. Their equivalent spring constant is: k₂₃ = k₂ k₃ k₂ + k₃ This combination is connected in parallel with spring k₁ . The total equivalent spring constant of the system is: k_ eq = k₁ + k₂₃ = k₁ + k₂ k₃ k₂ + k₃ = k₁ k₂ + k₂ k₃ + k₃ k₁ k₂ + k₃ When a constant force F is applied to the block, the equilibrium position shifts by a distance x₀ given by: x₀ = F k_ eq Since the block is initially at rest at the unstretched position, it will perform simple harmonic motion about