During most of its lifetime, s star maintains an equilibrium size in which the inward force of gravity on each atom is balanced by an outward pressure force due to the heat of the nuclear reactions in the core. but after all the hydrogen fuel is consumed by the nuclear fusion, the pressure force drops and the star undergoes a gravitational collapse until it becomes a neutron star. in a neutron star, the electrons and protons of the atoms are squeezed together by gravity until they fuse into neutrons. neutron stars spin very rapidly and emit intense pulses of radio and light waves, one pulse per rotation. these pulsing stars were discovered in the 1960's and are called pulsars. a) a star with the mass (m=2.0x10^30 kg) and size (r=7.0x10^8 m) of our sun rotates once every 30 days. after undergoing gravitational collapse, the star forms a pulsar that is observed by astronomers to emit radio pulses every 0.10 s. by treating the neutron star as a solid sphere, deduce its radius. b) what is the speed of a point on the equator of the neutron star? your answer will be somewhat too large because a star cannot be accurately modeled as a solid sphere. even so, you will be able to show that a star, whose mass is 10^6 larger than the earth's, can be compressed by gravitational forces to a size smaller than a typical state in the united states!

Explanation:

During this process the mass will be considered constant. We start from a radius and a period . The final period is .

Angular momentum L is conserved in this process. We can use the formula , where I is the momentum of inertia (which for a solid sphere is ) and is the angular velocity, so we can write the star's angular momentum as:

Since we have:

Which can be simplified as:

Which means:

Which for our values is:

And we calculate the speed of a point on the equator by dividing the final circumference over the final period:

most voltage drop calculators want the distance between the source and destination. then internally, they double it so both the source and return wires are calculated. but you need to know which distance the calculator uses so you're not half of what you should be or double what you should be.

most circuit breakers will not take a #6 directly, so the electrician will have to splice on a smaller pigtail. you also have to upsize the grounding wire when you upsized the ungrounded (hot) wire (see note in 250.122). this will preclude using most cable assemblies, as a cable with #6 copper will most likely only have a #10 grounding conductor. you need a #6 grounding conductor if the circuit is 20a. a #8 cable is no better, as it will have a #10 grounding conductor too. but most 20a breakers will take a #8 directly.

in your related post, you didn't say what type of load this is. if it is a light or heater, voltage drop won't be a big issue. if this is a motor, the current needs are huge at startup and the voltage drop can pose a problem. if this is a motor, knowing if the motor is under much load during startup will answer the voltage drop effect (a saw is easier to start than a compressor).

nah.   i'm just sleepy.