That tower question (1 Viewer)

[jeffwu95]

i think that you had to talk about both decreasing then increasing because it asked for changes

 

[RishBonjour]

i think that you had to talk about both decreasing then increasing because it asked for changes

but the magnet was already past half way and was only pulled out hence it was only attraction force I think. changes part threw me off. but if BOS expects both increasing an decreasing, then badly worded. "partly in"

 

[habitres]

i think that you had to talk about both decreasing then increasing because it asked for changes

Yea, so mass decreases slightly when it is pulled off, then goes back to normal/previous as the solenoid "goes away" as there is no more influence.
Its just attraction and then the absence of the solenoid.

 

[jeffwu95]

yup thats what i said ^_^

 

[RishBonjour]

Yea, so mass decreases slightly when it is pulled off, then goes back to normal/previous as the solenoid "goes away" as there is no more influence.
Its just attraction and then the absence of the solenoid.

oh fucked. 2/4 for that then.

 

[someth1ng]

You cannot say the mass changes because the mass stays the same. You can say the measured weight or the apparent weight etc but mass is not acceptable.

 

[Keelan134]

I said at Tower A the mass would drop straight down to North Pole as Tower A was just rotating on the spot. For Tower B I Said as the initial velocity of the mass is equal to the velocity of the tower, the mass will fall with the rotational speed of the tower and land at its base. I cited Galileo's explanation as to why when you jump the earth doesn't move beneath you because you are in the same frame of reference.

 

[someth1ng]

I said at Tower A the mass would drop straight down to North Pole as Tower A was just rotating on the spot. For Tower B I Said as the initial velocity of the mass is equal to the velocity of the tower, the mass will fall with the rotational speed of the tower and land at its base. I cited Galileo's explanation as to why when you jump the earth doesn't move beneath you because you are in the same frame of reference.

You should get 2 marks of the 4 marks.

 

[Keelan134]

Depends on the marking scheme- its impossible to tell. One or two I'd imagine.

And I know this is sorta off topic but just quickly, what did you guys get for the solenoid and balance question? Did you put that the balance reading increases or decreases?

Decreases as the magnet would have been attracted upwards to the solenoid as it left, Lenz Law would've produced mag fields opposing the change creating an attractive force to try and bring magnet closer. Sound any good?

 

[Keelan134]

Is this the reason for geostationary orbit? The orbital period on top of the Tower matches the rotational period of the Earth. Therefore its initial velocity generated from the rotation of the earth would be equal to that of a geostationary orbit due to its same altitude(orbital radius) and orbital period? The question also said discuss this thought experiment, as we learnt from that other skills question we got today to demonstrate how theory becomes validated, we must conduct experiments before we can get a true answer, therefore our thought experiments can be neither correct or incorrect, everyone gets 4 marks haha. They should get that Felix Baumgartner to jump from a geostationary orbit and see what happens

 

[Zeroes]

^lol that's actually precisely what I thought... "hmm, new challenge for Felix"

 

[ademb13]

does NOT achieve orbital velocity when dropped :/ so how can it orbit. at poles it lands directly below, at the equator a half parabolic motion to hit the ground due to movement of the tower due to earth's rotation

 

[Cruiseshipfan]

The mass in tower B orbits the earth. The reasons are:
1. The mass was at the height of a geostationary satellite
2. It had a period of 24 hours.

This tell us that it has the same period of orbit around the Earth as a geostationary satellite and is the same distance from the Earth as a geostationary satellite, so therefore when the mass is released it becomes a geostationary satellite and orbits the Earth (staying over the same location)

The mass has a greater speed then the same mass on the surface of the Earth, due to the tower the distance from the centre of the Earth is greater but the time taken for a complete rotation is the same, so therefore a greater velocity, this gives it enough velocity to maintain orbit.

This is as simple as I can explain it.

 

[ademb13]

dude it was dropped, regardless of its position it will fall to the earth. It is at a height of a geostationary orbit, however it is NOT orbiting the earth because it has not reached its orbital velocity. yes its orbital period is 24 hours when it is on the tower, but when it is dropped it will not be. Newtons law of gravitation says that it will move to the earth as it does not have the orbital velocity required for it to orbit.

 

[someth1ng]

dude it was dropped, regardless of its position it will fall to the earth. It is at a height of a geostationary orbit, however it is NOT orbiting the earth because it has not reached its orbital velocity. yes its orbital period is 24 hours when it is on the tower, but when it is dropped it will not be. Newtons law of gravitation says that it will move to the earth as it does not have the orbital velocity required for it to orbit.

Wrong. It will have a tangential velocity of the tower as according to Newton's FIRST law of motion, the object will maintain that motion. The velocity is large enough that the Earth will curve away as quickly as the object falls.

 

[cookeemonstah]

wrong. It will have a tangential velocity of the tower as according to newton's first law of motion, the object will maintain that motion. The velocity is large enough that the earth will curve away as quickly as the object falls.

stop killing my hope

 

[ademb13]

Wrong. It will have a tangential velocity of the tower as according to Newton's FIRST law of motion, the object will maintain that motion. The velocity is large enough that the Earth will curve away as quickly as the object falls.

well i guess the head teacher of physics at my school is wrong ? or maybe multiple answers are accepted along with justification? or maybe the object is dropped instead of thrown? think about a tower not that high (centerpoint tower, assuming its on equator) and assume atmospheric friction has no result, will it orbit in the sky?

 

[samaccount123]

lol..centerpoint tower....typical sydney icon..lets say eiffell tower, add variety to imagination =p

 

[viraj30]

i wrote that both objects will fall close to the base of the tower with some explanations....how many marks will i lose??

 

[manscux]

talked to teacher who has been head of Marking for quite a bit:

This is what he had to said you needed to get full marks

earth orbits its axis at roughly 1700km/h at an easterly direction.
for mass A since it as the pole, the top of the axis it will gain the horizontal component of earths velocity. But it falls to the ground below the tower because it has a constant downward (vertical) accerlationa cting on it.
For mass B the mass has a horizontal velocity same to that of the earth so RELATIVE to the sun an external observer will see it go in a parabolic motion around the earth before landing on the spot under the tower. It to has a constant vertical motion

IT DOES NOT GO IN GEOSTATIONARY ORBIT BECAUSE MY TEACHER GAVE ME A SIMPLE EXAMPLE AND THAN LAUGHED.....

PLEASE NOTE: A GUY WHO JUMPED OF QUITE HIGH RECENTLY IN A DAREDEVIL STUNT DID NOT GO INTO EARTH ORBIT.... HE WENT STARIGHT DOWN.... I THINK THAT EVIDENCE IS ENOUGH THAT RELATIVE TO THE SUN THE MASS WILL GO A PARABOLIC DECAY WHERE IT FALLS TO THE GROUND BENEATH THE TOWER RELATIVE TO eARTH