HSC Physics Question Thread

[conic curve]

Jamon I think I'm clear on my question now.

Statement: waves are a transfer of energy disturbance that may occur in one, two or three dimensions. Different waves in different media can travel in different numbers of dimensions. A longitudinal wave or slinky is 1d. A transverse or water wave is 2d. Sound waves or EM are 3d

What other examples are ther?

[jamonwindeyer]

Jamon I think I'm clear on my question now.

Statement: waves are a transfer of energy disturbance that may occur in one, two or three dimensions. Different waves in different media can travel in different numbers of dimensions. A longitudinal wave or slinky is 1d. A transverse or water wave is 2d. Sound waves or EM are 3d

What other examples are ther?

Yep you've got it!! I can't think of any other examples off the top of my head though 

[conic curve]

Yep you've got it!! I can't think of any other examples off the top of my head though 

A transverse wave is a wave which oscillates perpendicular to the direction of propagation. Is this something by definition and something that we need to accept without questioning why?

[zsteve]

A transverse wave is a wave which oscillates perpendicular to the direction of propagation. Is this something by definition and something that we need to accept without questioning why?

That's a definition so yeah, you'll need to accept it without questioning :3
Basically people noted that waves could occur in two distinct types and named them. It's like why we call a cat a cat and a dog a dog.
However, note that there exist waves which combine both transverse and longitudinal motion (very convoluted waves, they are). So that's your cogs and dats

[conic curve]

That's a definition so yeah, you'll need to accept it without questioning :3
Basically people noted that waves could occur in two distinct types and named them. It's like why we call a cat a cat and a dog a dog.
However, note that there exist waves which combine both transverse and longitudinal motion (very convoluted waves, they are). So that's your cogs and dats

This is the reason why cats are clawed cats and why dogs are called dogs: e English word cat dates from before 900 A.D. - comes from the Old English words: catt (male) and catte (female). The word comes from Old High-German / Old Norse words. The English word dog comes from before 1050 A.D. - again from the Old English word docga

Anyways getting back to physics why do CROs represent sound waves as transverse waves?

What is the difference between pitch and noise?

What are some other applications of echoes other than SONAR and ultrasound imaging?

[RuiAce]

This is the reason why cats are clawed cats and why dogs are called dogs: e English word cat dates from before 900 A.D. - comes from the Old English words: catt (male) and catte (female). The word comes from Old High-German / Old Norse words. The English word dog comes from before 1050 A.D. - again from the Old English word docga

Anyways getting back to physics why do CROs represent sound waves as transverse waves?

What is the difference between pitch and noise?

What are some other applications of echoes other than SONAR and ultrasound imaging?

"Noise" isn't even a term in physics.

[jamonwindeyer]

This is the reason why cats are clawed cats and why dogs are called dogs: e English word cat dates from before 900 A.D. - comes from the Old English words: catt (male) and catte (female). The word comes from Old High-German / Old Norse words. The English word dog comes from before 1050 A.D. - again from the Old English word dock

LOL

Anyways getting back to physics why do CROs represent sound waves as transverse waves?

What is the difference between pitch and noise?

What are some other applications of echoes other than SONAR and ultrasound imaging?

That first question is a loaded one, but basically, it is related to the operation of the CRO itself. The sound waves act as inputs to the CRO through a microphone, and CRO's are designed to represent the magnitude of the input R(in this case, the level of compression of the microphone) on the vertical axis of the screen. Thus, the longitudinal compressions are represented as transverse peaks, and the longitudinal rarefactions are represented as transverse troughs 

Pitch relates to how high or low a sound is, which is different to its volume. Noise is a generic term (it does have use in Physics though Rui, in electrical terms it refers to irregular fluctuations that accompany electrical signals), either way not really in the same category as pitch 

RADAR also uses the idea of echo location imaging, just with radio waves instead of sound waves!! 

[conic curve]

"Noise" isn't even a term in physics.

Huh? It said pitch is related to frequency and volume to amplitude of sound waves. The higher the frequency, the higher the pitch the noise is. The higher the amplitude, the louder it is

[jamonwindeyer]

Huh? It said pitch is related to frequency and volume to amplitude of sound waves. The higher the frequency, the higher the pitch the noise is. The higher the amplitude, the louder it is

Yeah! So noise is just used in the general sense, like, it's a noise. Like a tree falling in the woods, it doesn't have any specific meaning beyond the normal  so we refer to the pitch of that noise, and the volume of that noise 

[RuiAce]

Huh? It said pitch is related to frequency and volume to amplitude of sound waves. The higher the frequency, the higher the pitch the noise is. The higher the amplitude, the louder it is

Yes. Higher frequency = Higher pitch.

Noise is just a synonym for sound in that context.

[MysteryMarker]

Hey guys, need help with this question:

Describe what is meant by the term drift velocity, in terms of electrons moving in a solid conductor. Compare its magnitude to the thermal motion of electrons in a solid.

Cheers.

[conic curve]

Got a few questions to ask:

1. What does the gradient and the area represent in a displacement and velocity vs Time Graph?
2.  Why do we let one side (either left or right) be positive whenever solving with acceleration equations?
3. How is a force defined (other than a push, pull or a twist)?
4. What does it mean by "magnitude and direction"?

[RuiAce]

Got a few questions to ask:

1. What does the gradient and the area represent in a displacement and velocity vs Time Graph?
2.  Why do we let one side (either left or right) be positive whenever solving with acceleration equations?
3. How is a force defined (other than a push, pull or a twist)?
4. What does it mean by "magnitude and direction"?

1. If you had done calculus this would be more intuitive for you but in short
Gradient of displacement -> velocity
Gradient of velocity -> acceleration
Area under velocity graph -> distance travelled
Area under acceleration graph -> how much your velocity increased/decreased

Gradient of acceleration and area under distance are useless for HSC physics. The latter is in fact just useless altogether.

2. Because if left is positive and right is positive at the same time you go nuts. If left is positive but right is negative (or vice versa) you can compare: positive numbers mean left, negative numbers mean right.

3. You can use Newton's second law of motion here. The sum of all forces acting on an object is the scalar product of its mass with the acceleration. (F=ma)
Otherwise, just use the junior science definition

4. Magnitude = Has a value. E.g. 1 , 4, 61, 100
Direction = Has a direction. E.g. east, 235 degrees True bearing, North 1 degrees West, into the book

If it just has magnitude (e.g. amount of energy you use a day) then it's a scalar
If it has magnitude and direction (e.g. precisely how far north you travelled) it is a vector

[conic curve]

Thanks

1. Why is it difficult to see newton's first law?
2. What is the definition of a normal force (I tried to research this but don't understand it). Are normal forces the reaction force of gravity?
3. What is the relative velocity formula and what does it tell us?
4. For centripetal force, why do we say that objects travelling in a circular motion are still accelerating?
5. Why are speed limits a good idea

[jakesilove]

Thanks

1. Why is it difficult to see newton's first law?
2. What is the definition of a normal force (I tried to research this but don't understand it). Are normal forces the reaction force of gravity?
3. What is the relative velocity formula and what does it tell us?
4. For centripetal force, why do we say that objects travelling in a circular motion are still accelerating?
5. Why are speed limits a good idea

Where are you getting these questions from? Sounds like something out of a textbook, homework you're supposed to be doing or an Assignment. Don't mind if it's any but the last one, but just wondering!