Definitions Flashcards
Random error
Equally likely to be +ve or -ve. Gives a spread in results
Systematic error
Not revealed or reduced by simple repetition of measurements
Gaussian distribution
~68% of measurements in 1 s.d., 95% within 2 s.d.
Standard deviation formula
Error in the mean
Combining errors
Static and dynamic friction
Work done by a force
Potential energy
Potential energy and equilibrium
Newton’s Laws of Motion
Inertial frames
Speed of zero momentum frame
Centre of mass of a system
Moment vector
Moment of inertia (sum)
Moment of inertia (integration)
Parallel axes theorem
Perpendicular axes theorem (for a lamina in the x-y plane)
Describe the Michelson-Morley experiment
Optical interferometer used to measure speed of light in perpendicular directions by finding a shift in the interference pattern
If aether was real, light should be faster in one direction than the other, since the earth is moving
No shift was seen, therefore no evidence for aether. SPEED OF LIGHT THE SAME IN ALL REFERENCE FRAMES!
Stellar aberration
Light observed from distant stars appears to be coming in at an angle. Explained by relativity.
Evidence of special relativity
Muons reach Earth’s surface before decaying despite small lifetimes - time dilation
Michelson-Morley - no aether
Magnetic force between wires can be explained by modifying laws of electromagnetism with relativity
Clocks in space drift relative to earth - special and general relativistic effect
Einstein’s Postulates
- All the laws of physics are the same in any inertial frame
- The speed of light in a vacuum is the same for all observers
Lorentz transformations
SR transformation matrix
Space-time invariant
