Qualification > Sciences
Physics Paper4
ruby92:
--- Quote from: Sue T on May 08, 2011, 07:35:54 am ---hope im answering the ryt one :
paper 41 - 1ci) you have a gravitational field due to the earth, attracting any mass within its field to the left hand side of ur ppr , and you have another (smaller) gravitational field due to the moon attracting masses to your right hand side of th paper - (its smaller cuz the moon is smaller- simple) now at some point wont the resultant force exerted on unit mass, somewhere between the two planets, be equal and opposite? so thats why the grav field strength is zero
ii) grav. field strength = GM/r2 where M is the mass of the thing causing the field
so if the at a certain distance r from the centre of the earth - the grav field strengths of both planets are equal we form this eqn:
GMearth = GMmoon
_____ ____________
r2 (60RE-r)2
cancel the Gs and put in the masses - eventually you'll get ans answer in terms of RE
--- End quote ---
Thank you :D
basoom16:
--- Quote from: ruby92 on May 08, 2011, 07:40:09 pm ---Thank you :D
--- End quote ---
can u plz have a look at the question. its actaully 2 equations used. can u plz see it
Thanks
ruby92:
Yes GMm/r^2 =mw^r
but i dont understand what your doubt is then?
basoom16:
ah ok stupid me din calcualte properly. THANK U SOO MUCH :D
ruby92:
Your welcome and i'm sorry i'm very good at explaining.
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