Adding mass to a spring and then displacing it from its new equilibrium position before releasing it will result in vertical oscillations of the mass, with the spring providing the restoring force. These oscillations are described by simple harmonic motion.
To understand and describe the process you've mentioned, let's break it down into step-by-step stages:
1. Initial Equilibrium (Left-Most Figure):
- The spring is hanging vertically from a bracket at its unweighted equilibrium length.
- At this stage, there is no external force acting on the spring other than its own weight, so it's in equilibrium.
2. Adding Mass (Center Figure):
- An object with mass \(m\) is attached to the lower end of the spring.
- The mass is gently lowered until the spring reaches its new equilibrium length.
- At this point, the spring has been stretched or compressed from its original equilibrium position due to the added mass. The spring is now in a new equilibrium position, and it has experienced an elongation or compression.
3. Raising the Mass (Not Shown in Figures):
- Referring to the right-most figure (not explicitly shown), you mentioned that the mass is raised until the spring returns to its original length. This means the spring is being stretched beyond its new equilibrium position.
4. Release and Oscillations (Right-Most Figure):
- After the mass is raised beyond the new equilibrium position and then released from rest, vertical oscillations occur.
- These oscillations are a result of the spring's attempt to return to its equilibrium position. The mass will move up and down around the new equilibrium position, creating a simple harmonic motion.
- The mass will pass through the equilibrium position multiple times, with each oscillation being approximately symmetrical.
Key points to note:
- The spring is acting as a restoring force, trying to bring the mass back to its equilibrium position.
- The mass experiences periodic motion (oscillation) around this new equilibrium position.
- The frequency and amplitude of these oscillations depend on factors like the mass of the object, the spring constant (stiffness) of the spring, and any initial conditions (initial displacement or velocity) when released.