3.6.3
Energy in Simple Harmonic Motion
Conservation of Energy
Conservation of Energy
Energy cannot be created or destroyed so the total energy of the system must be conserved. The amounts of kinetic and potential energy are able to change.


Kinetic and potential energy
Kinetic and potential energy
- Kinetic energy comes from movement:
- Gravitational potential energy comes from a gain in height:
- Elastic potential energy comes from squashing or stretching a spring:


Total energy
Total energy
- At any point in the cycle, the total energy must be the sum of all the other energies and it must remain constant.
- In the centre of the oscillation, EPE is at a minimum and KE is at a maximum.
- At the top of the oscillation, KE is 0 and GPE and EPE are at a maximum.
Damped Oscillations
Damped Oscillations
In the real world friction acts on an oscillation object, this produces heat so reduces the amount of energy the object has. This will decrease the amplitude of the oscillations.


Damping
Damping
- When an oscillation is damped the amplitude of the wave decreases but the period and the frequency remain the same.
- A damping force is any force which opposes the movement of the object.


Types of damping
Types of damping
- If the damping on a system is small then the system is hardly affected, it will take a long time until you can see the amplitude reduce or the oscillations stop. This is under-damping.
- If the system has too much damping no oscillations will happen at all, the object will just slowly return to equilibrium. This is over-damping
- If the object returns to equilibrium as quickly as possible it has critical-damping.


Critical damping
Critical damping
- Critical damping is very desirable as it reduces oscillations quickly and can avoid damage.
- In car suspension, critical damping is needed for a comfortable and safe ride.
1Space, Time & Motion
1.1Motion
1.2Forces
1.3Momentum & Impulse
2The Particulate Nature of Matter
2.1Thermal Concepts
3Wave Behaviour
3.1Oscillations
3.2Travelling Waves
3.3Wave Characteristics
3.4Wave Behaviour
3.5Standing Waves
3.6Simple Harmonic Motion
3.7Single Slit Diffraction
3.8Interference
3.9Doppler Effect
4Fields
4.1Circular Motion
4.2Newton's Law of Gravitation
4.3Fields
4.4Fields at Work
4.5Electric Fields
4.6Magnetic Effect of Electric Currents
4.7Heating Effect of Currents
4.8Electromagnetic Induction
4.9Power Generation & Transmission
5Nuclear & Quantum Physics
5.1Discrete Energy & Radioactivity
5.2Nuclear Reactions
5.3The Interaction of Matter with Radiation
6Measurements
6.1Measurements & Errors
6.2Uncertainties & Errors
6.3Vectors & Scalars
Jump to other topics
1Space, Time & Motion
1.1Motion
1.2Forces
1.3Momentum & Impulse
2The Particulate Nature of Matter
2.1Thermal Concepts
3Wave Behaviour
3.1Oscillations
3.2Travelling Waves
3.3Wave Characteristics
3.4Wave Behaviour
3.5Standing Waves
3.6Simple Harmonic Motion
3.7Single Slit Diffraction
3.8Interference
3.9Doppler Effect
4Fields
4.1Circular Motion
4.2Newton's Law of Gravitation
4.3Fields
4.4Fields at Work
4.5Electric Fields
4.6Magnetic Effect of Electric Currents
4.7Heating Effect of Currents
4.8Electromagnetic Induction
4.9Power Generation & Transmission
5Nuclear & Quantum Physics
5.1Discrete Energy & Radioactivity
5.2Nuclear Reactions
5.3The Interaction of Matter with Radiation
6Measurements
6.1Measurements & Errors
6.2Uncertainties & Errors
6.3Vectors & Scalars
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