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3. Problem 11.44P (HRW) A pulsar is a rapidly rotating neutron star that emits radio
pulses with precise synchronisation, one such pulse for each rotation of the
star. The period T of rotation is found by measuring the time between
pulses. At present, the pulsar in the central region of the Crab nebula has a
period of rotation of T=o.033 s, and this period is observed to be
increasing at the rate of
(a) What is the value of the angular acceleration in
(b) If its angular acceleration is constant, how many years from now will the pulsar stop rotating? (c) The pulsar originated in a supernova explosion seen in the year A.D. 1054. What was T for the pulsar when it was born? (Assume constant angular acceleration since then.) |
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Solution: Click For PDF Version (a) Angular speed
Therefore,
We have been given that for the pulsar
Therefore, the angular acceleration of the pulsar is
(b) The present angular speed of the pulsar is
If the pulsar will continue to decelerate at this rate, it will stop rotating
at time
(c) As the pulsar was formed in 1054 A.D. its life till the present has been 949 y. Its period of rotation at the time of its birth
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and
period T are related as 
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