A typical neutron star may have a mass equal to that of the Sun but a radius of

Question

A typical neutron star may have a mass equal to that of the Sun but a radius of only 15 km.

(b) How fast would an object be moving if it fell from rest through a distance of 2.0 m on such a star? (Assume the star does not rotate.)



I already answered part a) which asked
(a) What is the gravitational acceleration at the surface of such a star?

** my correct answer to part a) is : 5.9e11 m/s^2

My attempt for part b) [marked incorrect] is 1.5e6 m/s but im not sure what I did wrong.. I tried to integrate the acceleration from part a) and define the veloctiy and position in terms of time. The only thing I can think of that may caused me to be wrong is that acceleration cant be treated as constant because it changes heights

Thanks

Explanation / Answer

The gravitational acceleration at the surface of the star g = 5.9*10^11 m/s^2

the height of the body released h = 2m

then the acceleration at height 2m is

                                 g' = g [ 1 -2h/R]

                                    = 5.9*10^11 [ 1 - 2(2)/15*10^3]

                                    = 5.898*10^11

From kinematic equations

   the final velocity v = 2gh

                               = 2(5.898*10^11m/s^2)(2m)

                                = 15.36*10^5 m/s or 1.54*10^6 m/s

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.