In: Physics
Neutron stars consist only of neutrons and have unbelievably high densities. A typical mass and radius for a neutron star might be 3.7 x 1028 kg and 1.3 x 103 m. (a) Find the density of such a star. (b) If a dime (V = 2.0 x 10-7 m3) were made from this material, how much would it weight (in pounds)?
Let the mass of neutron star (M) = 3.7× 
 kg
the radius of neutron star (R) = 1.3 × 
 m
a) Density 
 = Mass / Volume = M/V  
where Volume (V) = 4 π 
/3
  
=
3 M/4π 
substituting values
  
= 3× 3.7 × 
/ 4 ×π ×
×
= 4.0205×
kg /
The density of a star ( 
) = 4.0205 × 
 kg /
b) Given volume of dime (
)
= 2.0 × 

Weight (W) = mg = 
on substituting values
W = 4.0205 × 
 × 2.0× 
 × 9.8
= 7.88 ×
N
weight in lb = 7.88 ×
N × 1lb /4.448 N
= 1.7716 ×
lb