A neutron star is an extremely dense, rapidly spinning object that results from the collapse of a massive star at the end ofits life. A neutron star with 13 times the Sun's mass has an essentially uniform density of 4.8 x 1017 kg/ m3. (a) What's itsrotational inertia? (b) The neutron star's spin rate slowly de-creases as a result of torque associated with magnetic forces. Ifthe spin-down rate is 5.6 x 10-5 rad/s2, what's the magnitude of the magnetic torque?

(a). The rotational inertia is

(b). The magnitude of the magnetic torque is

Explanation:

Given that,

Mass of neutron

Density of neutron

(a). We need to calculate the rotational inertia

Using formula of rotational inertia  for sphere

...(I)

We know that,

Put the value of volume

Put the value of R in equation (I)

Put the value into the formula

The rotational inertia is .

(b). We need to calculate the magnitude of the magnetic torque

Using formula of torque

Put the value into the formula

The magnitude of the magnetic torque is

Hence, (a). The rotational inertia is

(b). The magnitude of the magnetic torque is

the answer is a. hope this .