- #1

- 249

- 1

## Homework Statement

Under some circumstances, a star can collapse into an extremely dense object made mostly of neutrons and called a neutron star. The density of a neutron star is roughly 10^{14} times as great as that of ordinary solid matter. Suppose we represent the star as a uniform, solid, rigid sphere, both before and after the collapse. The star's initial radius was 6.0×10^5km (comparable to our sun); its final radius is 16km

If the original star rotated once in 33 days, find the angular speed of the neutron star.

Express your answer using two significant figures and in rad/s

R

_{i}= initial radius

R

_{f}= final radius

## Homework Equations

Conservation of Momentum

I = 2/5MR^2

L = Iw

## The Attempt at a Solution

I first converted the 1 rev/ 33 days to rad/s

1/33 rev/ day *(2pi)*(1 day/24 hours)*(1hour/60 min)*(1 min/60 sec)

w = 0.000002 rad/s

I = (2/5)*(M)*(R

_{i}^2)*(0.000002) = (2/5)*(M)*(R

_{f}^2)w

_{f}

The masses (M) and the 2/5 cancel

3.6x10

^{17}= 2.56x10

^{8}*w

_{f}

w

_{f}= 1.40625x10

^{9}

It says it's wrong. The only thing that I can think of that is wrong is that I did the angular velocity (w) conversion wrong.

Last edited: