Multiple choice help!!! plus question using Newton's equation (1 Viewer)

[physician]

( 1 ) Communication satellites will eventually fall back to Earth. What causes this?

( a ) increased gravity as the satellite gets closer to Earth

( b ) atmospheric friction

( c ) increased velocity due to gravitational effects

( d ) increased velocity due to orbital decay


( 2 ) Use the following information to answer this question:

mass of Earth = 5.97 * 10²⁴
diameter of Earth = 12 756 km

universal gravitational constant, G = 6.67 * 10^-11 Nm²kg^-1

Newton's equation, F = Gm1m2/r²

( a ) Calculate the force of gravity between a 75 kg astronaut and the Earth

(i get 7.342 * 10⁸ N ..... TELL ME WHAT U GET PLEASE)

( b ) compare this with the weight of the astronaut





all help is greatly appreciated....

 

[KFunk]

Is this astronaut on earth or in space?

 

[physician]

Is this astronaut on earth or in space?

judging by the question I'd say space... (i.e astronaut)....
I don't think it's relevant as to where the astonaut is for the first question..

but for the second i think it does.. which is what's puzzling me...

but i presume that for the second we use Fw=mg
mass=75kg
g=9.8 m/s²

but what i dont get is how were supposed to "compare this (a) with the weight of the astronaut"....

 

[FinalFantasy]

( 1 ) Communication satellites will eventually fall back to Earth. What causes this?

( a ) increased gravity as the satellite gets closer to Earth

( b ) atmospheric friction

( c ) increased velocity due to gravitational effects

( d ) increased velocity due to orbital decay

i choose B: atmospheric friction


hmm.. i don't get how to do 2 unless they mention where that astronaut is

 

[physician]

hmm.. i don't get how to do 2 unless they mention where that astronaut is

unfortunately the question doesn't... but for the first part of question ( 2 ).. u don't need to know where the astonaut is... at least i don't think u do...

but i don't think the astronaut is on earth....

and anyways.. since mass is constant... we are able to calculate the astronauts weight on earth...
using Fw = mg.. as i mentioned in my previous post...

but if anyone can tell me what is meant when the question asks to compare.. i'd appreciate it...

ok and that's ( B ) for FinalFantasy... anymore takers...

 

[Xayma]

You need to know the distance between the center of masses, so Im guessing it is on Earth since that is th only measurement taken.

His weight is equal to the gravitational force between them.