Miscellaneous Circular Motion (1 Viewer)

[STx]

The force of attraction between the earth and its artificial satellite in circular orbit is given by F=GMm/x², where x is the distance of the satellite from the earth's centre, G is a constant, M is the earth's mass, m is the satellite's mass. A 500kg satellite is circling the earth at 4000 km above the surface of the earth. If the radius of the earth is 6400 km, find:

a) the gravitational force acting on the satellite given g=10m.s^-2 at the earth's surface

Theres other parts but this one is tricking me, i should be able to get the others if i get this one. ANS: 1890N

 

[bboyelement]

F = GMm/x^2

ma = GMm/x^2

a=GM/x^2

10=GM/(6400)^2

GM = 4.096 x 10^8

F = [(4.096 x 10^8) x 500]/(4000+6400)^2
equals to 1893N

 

[STx]

ah, thx

 

[STx]

Another one:
A smooth circular disc of radius 0.25 m rotates in a horizontal plane with angular velocity w=10 rad/s about a vertical axis through the centre O. A particle of mass m is attached at P by light inelastic strings to points M and N on the ends of a diameter of the disc, such that MP=0.4 m, NP=0.3 m and both strings remain taut. Find the tension in the string NP, and the mass m if the tension in MP is 20 N.

 

[STx]

^ anyone got any tips? please

 

[hectic18]

Another one:
A smooth circular disc of radius 0.25 m rotates in a horizontal plane with angular velocity w=10 rad/s about a vertical axis through the centre O. A particle of mass m is attached at P by light inelastic strings to points M and N on the ends of a diameter of the disc, such that MP=0.4 m, NP=0.3 m and both strings remain taut. Find the tension in the string NP, and the mass m if the tension in MP is 20 N.

I'd also like to know how to this question [ex 9F q8 from patel btw]

 

[jyu]

I'd also like to know how to this question [ex 9F q8 from patel btw]

ignore 'not required by the question'

 

[hectic18]

Ok I've got it now, cheers jyu