How Large Can a Pulsar Be Before Its Surface Exceeds Light Speed?

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Homework Help Overview

The discussion revolves around a problem related to pulsars, specifically focusing on the maximum radius of a pulsar that emits light without any part of its surface exceeding the speed of light. The context involves understanding the relationship between rotation, surface speed, and angular velocity.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants express difficulty in solving the problem and seek clarification on the relationship between rotation rate and surface speed. Questions about angular velocity and its connection to the surface speed of the pulsar are raised.

Discussion Status

Some participants have offered hints regarding the relationship between surface speed and angular velocity, suggesting a focus on the necessary rotation rate for the pulsar. There is a mix of attempts to solve the problem and requests for further guidance, indicating an ongoing exploration of the topic.

Contextual Notes

Participants mention a lack of understanding of the relevant chapter, indicating potential gaps in foundational knowledge that may affect their ability to engage with the problem fully.

akane
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ok, here we go. I got this problem and i can't figure out how to solve it.

A pulsar is a celestial object that emits light in short bursts. A pulsar in the Crab Nebula flashes at a rate of 30 time/s. Suppose the light pulses are caused by the rotation of a spherical object that emits light from a pair of diametrically opposed "flashlights" on it equator. What is the maximum radius of the pulsar if no part of its surface can move faster than the speed of light
(3.00 x 10 to the 8th m/s)?

Thanks a lot! I appreciate your help-

Akane
 
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please help me...i really need to figure out how to do this
 
anyone?> i tried solving it myself but no luck
 
What have you tried?

Here are a few hints:

Since there are two light sources, what rotation rate must the object have? What angular velocity?
What's the relationship between surface speed and angular velocity?
 
i am sorry but i still don't understand this chapter. If you could give me some more hints i would really appreciate it
 
The relationship between the surface speed at the equator and the angular velocity [itex]\omega[/itex] (which is measured in radians/sec) is [itex]v = \omega r[/itex].
 
thank you very much! it helped me figure out the problem. :cry: it was not that bad-
 

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