3.6.1 Further mechanics Flashcards
1
Q
What is meant by a radian?
A
Angle of a circle sector such that the radius is equal to the arc length
2
Q
What are the conditions for SHM?
A
- Acceleration is proportional to displacement from equilibrium position
- And acceleration acts toward equilibrium position
3
Q
What is resonance? What is the phase difference?
A
- When the driving force most efficiently transfers energy to the system
- pi/2
4
Q
What is a damping force?
A
- An opposing force that dissipates energy to the surroundings
- Damping is always is opposite direction to velocity
5
Q
What is critical damping?
A
When the amplitude is reduced to zero in the quickest time
6
Q
3 effects of increasing damping (think graph)
A
- Amplitude is lower at all frequencies
- Resonant peak is at a lower frequency
- Resonant peak is broader
7
Q
An example of resonance in real life?
A
Soldiers must break step when crossing bridges
8
Q
State the assumption about the pendulum for T=2pi sqrt(l/g) to be valid
A
Amplitude of bob is small
9
Q
What is meant by forced vibrations?
A
When the system is made to oscillate by a periodic external force
10
Q
What is meant by free vibrations?
A
- The natural oscillations that occur when a system is disturbed from its equilibrium position and then allowed to move freely, without any external force acting on it
- The system oscillates at its natural frequency
