A neutron star consists of neutrons at approximately nuclear density. Estimate, for a 10-km-diameter neutron star its mass number, its mass, the acceleration of gravity at its surface.

a) 7.2*10^55

b) 1.2*10^29 kg

c) 3.2*10^11 m/s

Explanation:

Given a diameter of 10 km, that's a radius of 5 km.

We first attempt to find its mass number

A = (r/1.2*10^-15)³

A = (5/1.5*10^-15)³

A = 7.2*10^55

This gotten mass number is then multiplied by the mass of each neutron in the star. With each neutron being, 1.7*10^-27

M = 7.5*10^55 * 1.7*10^-27

M = 1.2*10^29 kg

And finally, using the formula

g = GM/r², we can find its acceleration due to gravity.

g = (6.67*10^-11 * 1.2*10^29) / 5000²

g = 8*10^18 / 2.5*10^7

g = 3.2*10^11 m/s

a solenoid is created by wrapping a l = 90 m long wire around a hollow tube of diameter d = 4.5 cm.   the wire diameter is d = 0.9 mm.   the solenoid wire is then connected to a power supply so that a current of i = 9 a flows through the wire.

randomized variablesl = 90 m

d = 4.5 cm

d = 0.9 mm

i = 9 a                                          

write an expression for the number of turns, n, in the solenoid. you do not need to take into account the diameter of the wire in this calculation.

calculate the number of turns, n, in the solenoid.

write an expression for the length of the solenoid (l2) in terms of the diameter of the hollow tube d.

calculate the length of the solenoid (l2)   in meters.

calculate the magnitude of the magnetic field at the center of the solenoid in teslas.

explanation:

kepler used the data from tycho blahe (his mentor) to construct the laws of planetary motion.