# HSC Physics Marathon 2013-2015 Archive (1 Viewer)

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#### Mr_Kap

##### Well-Known Member
re: HSC Physics Marathon Archive

Sample asnwer says:

The principle of re
lativity states that it is not possible to detect motion with uniform velocity
while in one frame of reference without referring to another frame of reference. Thus, the
principle only applies for non
-
accelerating steady motion, which occurs in an inertial
frame of
reference. Within an inertial frame of reference, experiments or observations cannot be
performed which would indicate whether an object is stationary or moving with constant
velocity. The speed of light, c, is constant in inertial frames of refe
dilation, etc.

#### malcolm21

##### Active Member
re: HSC Physics Marathon Archive

How mcuh do we need to know about energy transformations in the home and industry? It's the last dotpoint in motors and I havent been able to find much info on it at all

#### Khan.Paki

##### Member
re: HSC Physics Marathon Archive

try hsc.csu. They have a good and brief coverage on that dot point

##### Breaking the limits.
re: HSC Physics Marathon Archive

How mcuh do we need to know about energy transformations in the home and industry? It's the last dotpoint in motors and I havent been able to find much info on it at all

It would most likely give a scenario, then maybe ask to identify some energy transformations in it.

#### Mr_Kap

##### Well-Known Member
re: HSC Physics Marathon Archive

How do you find centripital acceleration given the speed of an object travelling in a circle, and the radius of the object from the centre

#### Thjv

##### Member
re: HSC Physics Marathon Archive

a = v^2/r

#### Seanos_Nachos

##### New Member
re: HSC Physics Marathon Archive

Centripetal acceleration = v^2/r

Can be derived from Gmm/d^2 = mv^2/r

#### InteGrand

##### Well-Known Member
re: HSC Physics Marathon Archive

Centripetal acceleration = v^2/r

Can be derived from Gmm/d^2 = mv^2/r
Not really, since the centripetal force mv^2/r assumes the centripetal acceleration formula and then uses F = ma essentially, so this reasoning is circular (lol).

#### Mr_Kap

##### Well-Known Member
re: HSC Physics Marathon Archive

HELP!!

#### Seanos_Nachos

##### New Member
re: HSC Physics Marathon Archive

Not really, since the centripetal force mv^2/r assumes the centripetal acceleration formula and then uses F = ma essentially, so this reasoning is circular (lol).
Yes but the centripetal acceleration formula is the only one not on the HSC data sheet so I was referring to using the formulas given to you, to derive the formulae you need.

#### Seanos_Nachos

##### New Member
re: HSC Physics Marathon Archive

Through lenz's law and the right hand rule the conductor cutting flux induces a current to oppose the change which caused it (P to R)
Since the direction of current is the opposite to the direction of electron flow, there would be a concentration of electrons at P so the answer is (A)

#### Thjv

##### Member
re: HSC Physics Marathon Archive

Yes but the centripetal acceleration formula is the only one not on the HSC data sheet so I was referring to using the formulas given to you, to derive the formulae you need.
Yes, equate ma with mv^2/r

#### astroman

##### Well-Known Member
re: HSC Physics Marathon Archive

are faradays laws questions common, i never remember using the formula.

#### astroman

##### Well-Known Member
re: HSC Physics Marathon Archive

what would be the best diagram for dc motor?

#### astroman

##### Well-Known Member
re: HSC Physics Marathon Archive

Describe how magnetic fields can be produced by either by current carrying coils or permanent magnets. 2marks.

#### 123ryoma12

##### Member
re: HSC Physics Marathon Archive

Describe how magnetic fields can be produced by either by current carrying coils or permanent magnets. 2marks.
omg, that's like asking why 1 + 1 = 2.

#### EyyB0ss

##### New Member
re: HSC Physics Marathon Archive

Hey guys, new user here
Was wondering if anyone does Quanta. Could someone explain to me De Broglies hypothesis with reference to this question.

#### Mr_Kap

##### Well-Known Member
re: HSC Physics Marathon Archive

Describe how magnetic fields can be produced by either by current carrying coils or permanent magnets. 2marks.
I actually don't know this. lol.

How do i DESCRIBE it.
like i know its a fact but what's the answer?

#### Drsoccerball

##### Well-Known Member
re: HSC Physics Marathon Archive

I actually don't know this. lol.

How do i DESCRIBE it.
like i know its a fact but what's the answer?
When there is a current there is a magnetic field. Therefore by utilising current carrying coils we can also manipulate their produced magnetic field. This can either be use or a permanent magnet which also provides a magnetic field.

#### Mr_Kap

##### Well-Known Member
re: HSC Physics Marathon Archive

Am i right saying that when you travel at relativistic speeds your mass doesn't change to YOUR PERSPECTIVE????

Because to someone watchning it gets heavier.. but what about if YOU are travelling that fast?

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