Comparing Earth's Orbital & Rotational Periods

[JohnJay]

Homework Statement

What is the ratio of the Earth's orbital period about the sun to the Earth's period of rotation about its own axis

Homework Equations

none, theory

The Attempt at a Solution

Its theory

Two 335 kg masses (744 lb) are separated by a distance of 5 m. Using Newton's law of gravitation, find the magnitude of the gravitational force exerted by one mass on the other.

F = Gm1m2
______
r (squared)

God... I'm putting it in, but it says its wrong... help...



Joe has a weight of 750 N (about 170 lb) when he is standing on the surface of the earth. What would his weight (the gravitational force due to the earth) be if he tripled his distance from the center of the Earth by flying in a spacecraft ?

The formula should be...

w x a = f

help please!


Thank you members of the community

 

[Kurdt]

The first question should be fairly easy. I assume you've been given the information about both periods of rotation.

For the two masses what answer are you getting? That might help in diagnosing what's going wrong.

Weight is defined as W=mg, where:

$$g= G\frac{M_E}{r^2}$$

What will his weight be if r is tripled?

 

[Astronuc]

What is the ratio of the Earth's orbital period about the sun to the Earth's period of rotation about its own axis

What is the definition of a year timewise? What is significant about the length of a day?

For the second problem, please show the values used, e.g. gravitational constant, G, in the formula.

 

[JohnJay]

Umm it doesn't say...

and grav. should be 9.81

 

[Kurdt]

Umm it doesn't say...

and grav. should be 9.81

What do you think are the periods for the period of rotation of the Earth and the period of the Earth round the sun. Its fairly obvious.

No, g = 9.81 ms^-2 and G = 6.67x10^-11 m³kg^-1 s^-2