- #1

shk

- 78

- 8

## Homework Statement

Somewhere between the Earth and the Moon there is a point where the gravitational potential due to the Earth exactly equals that due to the Moon.

i)At what distance from the Earth is this point?

Mass of Earth = 5.98x10^24 kg

Mass of Moon= 7.35x10^22 kg

Distance between Earth and Moon = 3.84x1^8

ii) Is this the point at which the combined gravitational field is zero?Explain

b)

i) Explain why an astronaut in a spacecraft orbiting the Earth appears to be weightless?

ii)State the condition necessary for true weightlessness.

## Homework Equations

V=GM/r

g=Gm/r^2

## The Attempt at a Solution

I think

for part a ) i)

i need to equate the potential of moon and Earth to find the distance from the Earth.

for part a) ii)

I think the answer is no . because g is inversely proportional to r^2 and not r. but this pat is 3 marks so I may need to find that point by equation the g from moon and Earth. I am not really sure.

for b)i)

I think g is nearly zero in space so resultant force is zero. but this also doesn't make sense as there must be some forces as the astronaut is orbiting the Earth.

plus this is also 3 marks.

ii)I think weightlessness is when g is nearly zero