Dr George - HSC Physics Tutoring - Sydney

💡Physics tip:
How fast should this 360-degree pirate ship go so that the riders do not loose contact with their seats at top?
Minimum velocity is at which the Normal Force the seat exerts on the rider becomes zero.
v=√( ship radius x g)

💡Physics tip:
Time dilation is a physical phenomenon in which time moves differently for different observers in inertial frames of reference (in which there is no acceleration between them). The great Einstein said, the time passes faster on relatively slow objects e.g earth than on a faster objects e.g spaceship (the spacecraft clock ticks slower) depending on how fast the spacecraft travels.
In 1971, Hafele and Keating verified time dilation phenomenon at low relative velocities by flying extremely accurate atomic clocks around the Earth on commercial aircrafts.

💡Physics tip:
Doppler’s Effect
The wavelength or frequency of a wave is influenced by the wave’s relatively velocity to the observer.
If the emitter or source of wave is moving towards the observer, the resultant wave has shorter wavelength (blue shifted) and greater frequency.
If the emitter or source of wave is moving away from the observe, the resultant wave has longer wavelength (red shifted) and lower frequency.
We apply Doppler effect to study the movements of stars by studying the spectrum of their emitted light (Mod 7)
Also, Hubble used the Doppler shift of hydrogen absorption lines to determine the galaxies' velocities relative to Earth. Hubble discovered that almost all spectral lines were red-shifted and deduced that the universe is expanding (Mod 8)
Doppler effect applies to sound as it does to light. Watch this clip.

Doppler Sound Waves Pulse weather radars measure the wind field by harnessing the Doppler effect. This is the shift in wave frequency due to the movement of the wave source rela...

💡Physics tip:
Both Huygens’s and Newton’s models can be used to explain how the light changes direction as it leaves the air and enters the glass prism.
Huygens wave model of light stated that every point on the wavefront was a source of secondary wavelets that then travelled forwards at the same speed and wavelength as the original wave. When encounters the glass prism, it slows down and refracts because the wavelength changes; thus, the wave also changes direction.
Newton’s corpuscular model of light assumes that the speed of light increases as it enters the glass prism because the light and
glass particles are attracted to each other.

💡Physics tip: Common shapes of curves in physics relationships

💡Physics tip:
The motor effect refers to the phenomenon where a current-carrying conductor experiences a force in an external magnetic field. The direction of the force is determined by the right-hand palm rule (explained in moving charges in magnetic fields

💡Physics tip: Effect of Electrical filed vs Magnetic field on charged particles.
A key difference between the two fields is that a Magnetic field affects only moving charges, while an electric filed affects any charge regardless of its motion.

Physics tip:
Continuing with understanding the question is a key step to correctly answering it.

Deduce: Draw conclusions
Define: State meaning and identify essential qualities
Demonstrate: Show by example💡
Describe: Provide characteristics and features
Discuss: Identify issues and provide points for and/or against
Distinguish: Recognise or note/indicate as being distinct or different from; to note differences between

Source: NEW SOUTH WALES EDUCATIONAL STANDARDS AUTHORITY (NESA)

💡 Physics tip:
Understanding the question is a key step to correctly answering it.

Evaluate: Make a judgement based on criteria; determine the value.
Analyse: Identify components and the relationship between them; draw out and relate implications
Appreciate: Make a judgement about the value of
Calculate: Ascertain/determine from given facts, figures or information
Assess: Make a judgement of value, quality, outcomes, results or size
Critically (analyse/evaluate): Add a degree or level of accuracy depth, knowledge and understanding, logic, questioning, reflection and quality to (analyse/evaluate)

Source: NEW SOUTH WALES EDUCATIONAL STANDARDS AUTHORITY (NESA)

💡Physics tip:
Diffraction of sound: not only light waves undergo diffraction, Differentiation occurs in all type of waves. For example, you can hear the conversation in the next room even though you cannot see the source. This is because sound waves undergo diffraction, bending and spreading as they go through the doorway between the two rooms. Diffraction only occurs when the wavelength is close to the size of the opening or object.

💡Physics tip:
Diffraction of light: Light waves travel in straight lines. HOWEVER!!!, diffraction is the bending and scattering behaviour a wave exhibits when it travels through a small opening or around edges.
The scattering process bends light’s direction of propagation. The degree of bend is dependent on the relative difference between its wavelength and size of the slit.
Diffraction cannot be explained by Newton corpuscles as they travel in straight lines only. But can be explained by Huygens wave theory