gravitational field helpp.. (1 Viewer)

[shantu1992]

heey

5. when a sphere of lead is placed 40.cm from another sphere of lead of mass 10.kg the gravitational force of attraction between the two lead spheres is found to be 8 * 10 to the power -8 N. what is the mass of the first sphere?

7. In an imaginary solar system, the star has a mass of 10 to the power of 30 kg, and a planet with a mass of 10 to the power of 22 kg orbits it with an orbital radius of 3 * 10 to the pwer of 12 m

(A) CALculate the centripetal force acting on the planet
(b) calculate the period of teh planet
(c) if the planet has radius 8000 km, calculate the gravitational field on its surface
(d) calculate the gravitational field 2000 km above the surface of thsi planet


im really stuck on these two
i would appreciate some of your help
thankkss!

 

[3unitz]

5. when a sphere of lead is placed 40.cm from another sphere of lead of mass 10.kg the gravitational force of attraction between the two lead spheres is found to be 8 * 10 to the power -8 N. what is the mass of the first sphere?

F = Gm₁m₂/d^2

F = 8*10^-8
G = 6.67*10^-11
m₁ = 10
d = 0.4

sub into equation and solve for m₂

7. In an imaginary solar system, the star has a mass of 10 to the power of 30 kg, and a planet with a mass of 10 to the power of 22 kg orbits it with an orbital radius of 3 * 10 to the pwer of 12 m

(A) CALculate the centripetal force acting on the planet

the centripetal force is equal to the gravitational force:

F = Gm₁m₂/d^2

G = 6.67*10^-11
m₁ = 10^30
m₂ = 10^22
d = 3*10^12

sub into equation to find F

(b) calculate the period of teh planet

to find the period we need the velocity of the planet. we can find this from the centripetal force formula:

F = mv^2/r

F = answer of part (a)
m = 10^22
r = 3*10^12

sub into equation and solve for v.

the period is then given by T = 2*pi*r / v

(c) if the planet has radius 8000 km, calculate the gravitational field on its surface

g = Gm/r^2

G = 6.67*10^-11
m = 10^22
r = 8000 x 10^3

sub into equation to find g.

(d) calculate the gravitational field 2000 km above the surface of thsi planet

g = Gm/r^2

G = 6.67*10^-11
m = 10^22
r = (8000 + 2000) x 10^3

sub into equation to find g.