Why is the motion of a piston considered to be simple harmonic motion?

In summary, the motion of a piston is considered simple harmonic because it can undergo small vibrations in an isolated system without any damping forces. The mass of the piston and connecting rod only affects its time period, not its ability to undergo simple harmonic motion. Even a pendulum with a mass of 20g can also undergo simple harmonic motion.
  • #1
SonicBoomxxx
2
1
I know this is simple, but I don't fully understand why the motion of a piston is considered to be simple harmonic? Wouldn't the piston and connecting rod have mass?
 
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  • #2
What does their mass have to do with anything?
 
  • #3
With an infinitely long connecting rod, you would have comparable acceleration and velocity values for the piston and crank pin.
 
  • #4
A piston can have any motion you want. Are you talking about some very specific application of a piston?
 
  • #5
Simple harmonic motion is for small vibrations in an isolated system(free from damping forces). If you have a pendulum of mass 20g it can also undergo shm. Mass just affects it's time period. A piston can also undergo shm.
 

1. What is simple harmonic motion?

Simple harmonic motion is a type of periodic motion in which an object moves back and forth in a straight line with a constant frequency and amplitude. This motion is characterized by a restoring force that is directly proportional to the displacement of the object from its equilibrium position.

2. Why is the motion of a piston considered to be simple harmonic motion?

The motion of a piston is considered to be simple harmonic motion because it follows the same characteristics as described above. The piston moves back and forth in a straight line with a constant frequency and amplitude, and its motion is caused by a restoring force that is proportional to its displacement from the equilibrium position.

3. What is the role of the restoring force in simple harmonic motion?

The restoring force is responsible for bringing the object back to its equilibrium position when it is displaced. In the case of a piston, the restoring force is provided by the pressure of the gas or fluid inside the cylinder, which pushes the piston back towards its starting position.

4. How does the motion of a piston affect the performance of an engine?

The motion of a piston is crucial for the operation of an engine. As the piston moves back and forth, it converts the energy from the expanding gas into mechanical energy, which is used to power the engine. The piston's simple harmonic motion allows for smooth and efficient operation of the engine.

5. Can the motion of a piston deviate from simple harmonic motion?

In ideal conditions, the motion of a piston can be considered as simple harmonic motion. However, in real-world scenarios, external factors such as friction and non-uniform pressure can cause the motion to deviate from the idealized pattern. These deviations may affect the performance of the engine and need to be carefully managed and minimized.

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