Gravity and Satellites

[methodsboy]

Hey
im in a bit of a pickle with this one:
Neptune has a mass of: 1.02 x 10^26 kg
It's moon, Triton has mass : 2.14 x 10^22 kg and has an orbital radius of 3.55 x 10^8 m
For triton, calculate its:
- orbital acceleration


The answer is 5.40 x 10^-2 m/s^2   but i keep getting it wrong.

Anyone out here willing to help?

[methodsboy]

Mao? True Tears? Edmond?  ANYONE?

[Mao]

orbital acceleration as in centripetal acceleration, i.e. Neptune's gravitational field strength at the orbital radius

[Edmund]

I think:

Use F = G.Mm / r^2

Then, F = ma, where m is mass of Triton


EDIT: Yeah look at Mao's... I don't know how to use Latex...

[methodsboy]

orbital acceleration as in centripetal acceleration, i.e. Neptune's gravitational field strength at the orbital radius

where did u get 6.67E -11 from?

[TrueTears]

orbital acceleration as in centripetal acceleration, i.e. Neptune's gravitational field strength at the orbital radius

where did u get 6.67E -11 from?

Remeber G is a constant, better known as universal gravitational constant,
(obviously this is different from g, small case, which is 9.8 )

[methodsboy]

oh LOL sorry.... i was meant to say 1.02 x 10^26.
just realized that M is for the bigger mass hence 1.02 x 10^26
b4 i kept using mass of triton and thats why i didnt get anywhere
Thanks all

[TrueTears]

oh LOL sorry.... i was meant to say 1.02 x 10^26.
just realized that M is for the bigger mass hence 1.02 x 10^26

yah, remember the M (capital M) is always the mass of the object being orbited. So like for the moon orbiting around the earth, M would be the mass of the earth. Or for earth orbiting around the sun, M would be the mass of the sun.