Am I right here for Q23 of 2012 HSC physics paper? the towers in LEO question (1 Viewer)

[darkfenrir]

So it has a tower at the north pole and a tower at equator and it asks what will the motion be of masses dropped from each tower. I think since there is no linear orbital velocity for the object dropped from tower A, ie the earth's rotational motion of 465ms from east to west has no effect on the objects velocity, then (ignoring air resistance) it should fall straight down right? and at tower B the rotational motion of the earth at 465ms adds to the velocity of the object causing it to fall in a parabolic trajectory back down to earth. Am I right here? and I think the question was 4 marks. Would an answer such as this (obviously with some tidying of phrases) get full marks?

 

[Henry Thai]

Not sure if you still need help with this but I shall anyway. The question actually states the towers are at the altitude of a GEO orbit, which has the same period of rotation as the Earth. You are partially correct about the motion of the object dropped from tower A, but you should also mention the increasing acceleration as it nears the surface due to the effects of gravity. As for the object dropped from tower B, you needed to think about it carefully. An object dropped from the top of the tower will be in GEO orbit, which has a period of 24 hours. However, the Earth also rotates at a period of 24 hours, thus moving the entire tower along as it rotates. The result is that the object will not fall and will not move relative to tower B. This should get you 4 marks.

 

[someth1ng]

^That is correct.

 

[jamesischool]

damn i was going to answer this since i did it last year