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I am a superman [:D] . I lift a helicopter from earth and go a certain height above the earth . Then i wait for earth to rotate , and soon america comes right below me and i come down . Hence i reach america .
Is this possible ??
Assume that america does come under me for sure , wherever be my original position and also assume that i have a lot of time [:)]
Comments (45)
Hmm, since superman is superman so ofc he can do anything but the thing is he is carrying a helicopter(I wonder why) which has mass and this will create any diff if any.
But I do think superman(not you :p) can do what you claim.Ofc I am seeing this question as purely ideal situation i.e no air friction , no energy letdowns for superman n all xD.
Ofc I am wrong, but looking forward to your answer anchit.
nope, not possible. assuming superman is ideal and there is no wind / horizontal thrust, superman will remain at his position relative to the earth
although if he goes too high or remains too long like this he may get thrown outta atmosphere into space tangentially... so if superman were to be kind enuf to stop lifting helicopters for timepass / verfiying laws of physics and get back to saving the earth from evil villains...
well i say sumtin lik this:
suppose u get out of a moving bus.n the road has no friction u will continue to be moving along the st line in which the bus was travelling wen u got down.(basically inertia of motion)
now if the superman+copter plan to go st upwards towards the sky(wid the idea of reaching the reqd ht),the r already moving in a non st direction due to the vertical vel of his n the initial tgt vel provided by the earth
the thing is tht when he brings his vertical vel to 0..he thinks he is stationary but the fact his he still has the tgt vel.. which is too high(even in superman terms) now when he returns HE WILL NOT RETURN TO THE SAME PLACE
cuz tho tho he is given earths tgt vel he moves horizontally due to tht,but the pt from which he took of is moving in a circular path..another fact to be noted is tht the dist travelled to go up to come down may not be the same due to the fact tht earth is almost circular(spherical in the 3D sense)
so in order to reac some other spcific place he also has to provide himself a diff hor vel to counter earths hor vel..this is wat planes essentially do i think
but my conclusion is tht in this scenario if he attains decent height then he will not reach the same pt when he comes down...this is due to the fact tht earth's rotation gives him a hor vel(tgt vel) but the earth moves a circular path...
he cud have landed back @ the same pt only if the earth was able to give him a kind of rotational vel..which is impossible..
in a simple way wat im saying is tht in the bus+man scenario the man runs along wid the bus only as long as the bus continues to move in the same dir in which it was moving when he got down..if it takes a turn etc he wont be running along wid it
or u can say when ppl get off a moving merry-go-round the will run in the tgt direction but along wid the merry-go-round which is rotating.
i hope i make myself cleat
That's a simple problem and I don't think that it has much scope for debate .
See , Ultimator has given the correct answer . When , u are on ground , u have the same tangential velocity as that of earth. When u go up there is no force in the tangential direction of motion ( gravity acts downwards ). So according to the first law u retain the same velocity and ur relative position wrt the earth is fixed . So the claim that u have made in ur qn is not feasible .
Got it ?
@computer , plz make ur agrument to the point and brief . U are claiming that he should come down at a different point . That's possible iff he is acted by an external force in the direction of earth's tangential velocity .
Where does the force come into the picture ?
That's possible for some jet-like motion but that is not mentioned here . Plz elaborate a little bit using force concept in the current scenerio without using any analogy ,as they are often misleading !!
Also try to understand that as the helicopter flies at a height very much small compared with respect to radius of earth , we may also restate the problem as just like a converyer-belt passing down and a man standing on the belt throws a stone right up into the air and whether he will be able to catch the stone or not .
Surely he catches it !! ( Ground and belt , Both being inertial ref. frame )
@ feynmann:
im not talkin abt any external force @ all!!
if the man jumps on a bus he comesback to the same position if bus moves st..
but wat abt in a merry go round?? it has circular motion...a man jumping WILL NOT land on the same spot cuz he is give a tgt velocity but the belt does not (in the material sense)move in the tgt direction!! so in circular motion this jumping will not land the man on same position
Remember H<<R
so it is basically a one dimensional plane kinematics , not a circular one !!
But if u want to be veryyyyyyyyyyyyyyyy precise , then it has to be given a very careful thought . U have to solve the differential eqn of motion .
And then we can come to the exact solution .
Do u wanna try ?
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is the question tagged with academic or r u joking