Astronomy Basics: Solving Problems with Earth & Mars

  • Thread starter Thread starter vintagechic1251
  • Start date Start date
  • Tags Tags
    Astronomy Bit
AI Thread Summary
The discussion revolves around solving two problems related to orbital mechanics and gravitational attraction. For the first problem, the user is trying to calculate Mars' orbital period using Kepler's third law but is confused about unit conversions and the resulting high values. The second problem involves finding the mass of a second sphere based on the gravitational force between two spheres, but the user is uncertain about how to apply the gravitational force formula correctly. Participants suggest checking unit conversions and applying Kepler's laws properly for the first problem, while also clarifying the gravitational force equation for the second. Overall, the user seeks guidance on both problems to arrive at reasonable answers.
vintagechic1251
Messages
2
Reaction score
0
yes, i am defintely not a genius at this stuff...

i am having some problems figuring these two problems out:

Earth is 1.5x10^11 m from the Sun and has a period of 365.2 days. Mars is an average of 2.28x10^11 km from the sun. what is the orbital period of Mars in Earth years?

i am not exactly sure on what to do. should i convert m to km or the other way around? and i am not exactly sure on what equation to use either. i have used keplers third law to come out with an equation of the period of Mars is equal to the square root of the Earth's period squared times the radius of Mars over the radius of Earth cubed... i am getting really high answers like 5612 days and such. am i missing something?

i am also having problems with:

two spheres are 1.02 km apart. one of the spheres has a mass of 57.0 kg, and the force of attraction between the spheres is 1.79x10^-14 N. find the mass of the other sphere.

i'm not exactly sure on how to do that one because of the "force of attraction" i am not sure where i plug that value into. i have an equation of force times radius squared over gravitational force (6.67x10^-11) times the mass of the first sphere. and the answer i get when i do this is slightly unreasonable.

your help is greatly appreciated :smile:
 
Last edited:
Physics news on Phys.org
I'm not totally sure how to do the first part, but I'd check into Kepler's laws. You should take a look at your units too; perhaps you mean miles, not meters for Earth's radius of rotation.

For the second part, remember that the gravitational interaction between tow objects is found by:

F = (G*m1*m2)/r^2

G is a constant: 6.674E-11
 
Last edited:
seang said:
I'm not totally sure how to do the first part, but I'd check into Kepler's laws.

In particular the third one. :smile:
 
well i have done the third law and i get a really high answer which i am pretty sure can't be right.
 
vintagechic1251 said:
well i have done the third law and i get a really high answer which i am pretty sure can't be right.

Could you show us what you did?
 
Thread 'Collision of a bullet on a rod-string system: query'

Thread 'Collision of a bullet on a rod-string system: query'

In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question. Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point? Lets call the point which connects the string and rod as P. Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
View full post »
Thread 'A cylinder connected to a hanged mass'

Thread 'A cylinder connected to a hanged mass'

Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
View full post »

Similar threads

Gravitational potential energy traveling from earth to mars
Replies
7
Views
3K
Calculating Escape Velocity for Earth: Where Am I Going Wrong?
Replies
2
Views
2K
Martian's Weight on Mars Calculated
Replies
8
Views
2K
Calculating Tidal Range (Gravitation)
Replies
12
Views
2K
Astronomy - synodic/sidereal periods
Replies
2
Views
2K
Angular momentum for a shrunken Earth
Replies
11
Views
2K
Hohmann transfer towards mars: True Anomaly of Earth/ Launch date
Replies
6
Views
5K
Find the apogee from v at perigee, perigee, g, and the radius of Earth
Replies
3
Views
2K
Calculating Earth's Effective Spring Constant for its Orbit Around the Sun
Replies
8
Views
2K
Calculating the Period of Mars in Earth Years Using Gravitational Equations
Replies
12
Views
5K

Hot Threads

Recent Insights

Back
Top