Question

19) A planet 'P' has mass 'm' and distance from sun 'r while another planet 'Q' has mass m/2 and
distance from sun 3r'. Determine the ratio of gravitational pull due to sun on 'P' to that on 'Q'

Answer 1

Answer:

Given the periheleon=r  

2

​  

 

distance of planet from sun=r  

1

​  

 

Planet's mass=m

mass of sun=M

Length of major axes of no elliptical orbit=r  

1

​  

+r  

2

​  

 

Semi-major axis=R=(  

2

r  

1

​  

+r  

2

​  

 

​  

)

by Kepler's law

T  

2

∝R  

3

 

T∝R  

2

3

​  

 

 

T∝(r  

1

​  

+r  

2

​  

)  

2

3

​  

 

 

T=2π  

8GM

(r  

1

​  

+r  

2

​  

)  

2

 

​  

 

​