Gravity of the sun

1. Oct 17, 2004

guru

What is the acceleration due to gravity of the sun at the distance of the earth's orbit?

i have no idea where to begin.
Help

2. Oct 17, 2004

Tide

The gravitational pull of the Sun on the Earth is the centripetal force keeping the Earth from flying off into the great beyond.

3. Oct 17, 2004

geometer

Find the mass of the sun, and the distance between the sun and the earth. Then, think about Newton's Law of Universal Gravitation.

4. Oct 17, 2004

guru

This is what i obtained
Sun's Mass: 1.99x10^30 kg,
earth-sun distance: 150x10^6 km.

law of gravitional = Gm/r^2
G=6.67*10^(-11)

((6.67*10^(-11)) * (1.99*10^30))/ (2.25*10^12)

is that right?

Last edited: Oct 17, 2004
5. Oct 17, 2004

pervect

Staff Emeritus
Probably the simplest and most direct approach is to use Newton's law of gravity.

Do you know what that is?

6. Oct 17, 2004

guru

law of gravity = Gm/r^2
G=6.67*10^(-11)

((6.67*10^(-11)) * (1.99*10^30))/ (2.25*10^12)
right?

7. Oct 17, 2004

Tide

The acceleration due to the Sun's gravity at the location of the Earth is just

$$a = \frac {v^2}{R}$$

where v is the speed of the Earth around the Sun and R is the radius of Earth's orbit. You know R and you know the Earth travels a distance of $2\pi R$ in one year so you know its speed too.

8. Oct 18, 2004

geometer

That should be right!