In: Physics
A neutron star has a mass of 3.35 × 1030 kg (about the mass of our sun) and a radius of 6.09 × 103 m. Suppose an object falls from rest near the surface of such a star. How fast would it be moving after it had fallen a distance of 0.013 m? (Assume that the gravitational force is constant over the distance of the fall, and that the star is not rotating.)
Mass M = 3.35 × 1030 kg
Radius R = 6.09 × 103 m
Distance travel S = 0.013 m
Accleration due to gravity on star g = GM/R 2
Where G = Gravitational constant = 6.67 x10 -11 Nm 2/ kg 2
Substitute values you get g = ( 6.67 x10 -11) (3.35 × 1030 )/( 6.09 × 103 ) 2
= 6.024 x10 12 m/s 2
Initial speed u = 0
From the relation v 2 - u 2 = 2aS
v 2 - 0 2 = 2gS Since accleration a = g
v = [2gS]
= [2x 6.024 x10 12 x0.013]
= 395.78 x10 3 m/s