okay
q.
calculate hoe far an astronaut would need to be above the earth in order for his weight to be 0.01 his weight on the earths surface
i did it like this, Force or weight on the surface is F1.
the force at the distance from the surface where the astronauts weight is 0.01 that on the surface as F2
F1=100F2
F1=Gm1m2/r^2
F2=Gm1m2/(r1)^2
therefore
100/(r1)^2=1/r^2
r=6378000
take the inverse of both sides
(r1)^2/100=6378000^2
r1=637800
minus the radius of the earth i get a negative number XD
WTF!!!!!!!!!!
second way i tackled it
f=mg
f1=100f2
mg=100m(g1)
g1=.098
g1=Gm/r^2
r^2=Gm/g1
r=63765km
minus the radius of the earth
distance from earth = 57387km
wrong answer!!!!!!!!!!
then i did 0.01=gm1m2/r^2
we dnt know the mass of the astronaut, but thats wnt make a large diff to the answer, in theory it shouldnt make any difference but anyway i used it as 80
solving for r i get
r=199616081.5metres
and OMFG i found the correct answer, i never minused the radius of the earth at this point which will then get me the correct answer at 1.93x10^5
okay
why dnt the other ways i tried work?
any1 know?
q.
calculate hoe far an astronaut would need to be above the earth in order for his weight to be 0.01 his weight on the earths surface
i did it like this, Force or weight on the surface is F1.
the force at the distance from the surface where the astronauts weight is 0.01 that on the surface as F2
F1=100F2
F1=Gm1m2/r^2
F2=Gm1m2/(r1)^2
therefore
100/(r1)^2=1/r^2
r=6378000
take the inverse of both sides
(r1)^2/100=6378000^2
r1=637800
minus the radius of the earth i get a negative number XD
WTF!!!!!!!!!!
second way i tackled it
f=mg
f1=100f2
mg=100m(g1)
g1=.098
g1=Gm/r^2
r^2=Gm/g1
r=63765km
minus the radius of the earth
distance from earth = 57387km
wrong answer!!!!!!!!!!
then i did 0.01=gm1m2/r^2
we dnt know the mass of the astronaut, but thats wnt make a large diff to the answer, in theory it shouldnt make any difference but anyway i used it as 80
solving for r i get
r=199616081.5metres
and OMFG i found the correct answer, i never minused the radius of the earth at this point which will then get me the correct answer at 1.93x10^5
okay
why dnt the other ways i tried work?
any1 know?